Gesture based vehicle movements control and alerting system docu

GESTURE BASED VEHICLE MOVEMENTS CONTROL AND

ALERTING SYSTEM

INDEX

CONTENTS

1. Abbreviations

2. Figure Locations

3. Introduction

4. Block Diagram

5. Block Diagram Description

6. Schematic

7. Schematic Description

8. Hardware Components

Micro controller

LCD Display

Power Supply

MEMS

Voice IC

L293D

9. Circuit Description

10. Software components

a. About Keil

b. Embedded ‘C’

11. Source Code

12. Conclusion (or) Synopsis

13. Future Aspects

14. Bibliography

ABBREVIATIONS

Symbol Name

ACC Accumulator

B B register

PSW Program status word

SP Stack pointer

DPTR Data pointer 2 bytes

DPL Low byte

DPH High byte

P0 Port0

P1 Port1

P2 Port2

P3 Port3

IP Interrupt priority control

IE Interrupt enable control

TMOD Timer/counter mode control

TCON Timer/counter control

T2CON Timer/counter 2 control

T2MOD Timer/counter mode2 control

TH0 Timer/counter 0high byte

TL0 Timer/counter 0 low byte

TH1 Timer/counter 1 high byte

TL1 Timer/counter 1 low byte

TH2 Timer/counter 2 high byte

TL2 Timer/counter 2 low byte

SCON Serial control

SBUF Serial data buffer

PCON Power control

Figure Locations

S.No. Figure Page No.

1Components of Typical Linear Power Supply

2 An Electrical Transformer3 Bridge Rectifier4 Bridge Rectifier Positive Cycle5 Bridge Rectifier Negative Cycle6 Three terminal voltage Regulator7 Functional Diagram of Microcontroller8 Pin Diagram of Microcontroller9 Oscillator connections10 External clock drive connections11 A register12 B register13 RAM14 RAM Allocation15 Register Banks16 PSW17 DPTR18 SP19 PORT 020 TL0 and TH021 DB922 Connecting Microcontroller to PC23 Types of SIM Structures24 Smart Card Pin-out25 Smart Card Reader26 LCD27 MAX 232 Pin-out28 MAX 232 Operating circuit29 MAX 232 Logic output30 Project 31 New Project32 Select Target device 33 Select device for Target34 Copy 8051 startup code35 Source group 136 New file37 Opened new file38 File Save

39 Add files to the source group40 Adding files to the source group41 Compilation42 After Compilation43 Build44 Selecting the Ports to be visualized45 Start Debugging

INTRODUCTION

EMBEDDED SYSTEM:

An embedded system is a special-purpose system in which the computer is completely

encapsulated by or dedicated to the device or system it controls. Unlike a general-purpose

computer, such as a personal computer, an embedded system performs one or a few predefined

tasks, usually with very specific requirements. Since the system is dedicated to specific tasks,

design engineers can optimize it, reducing the size and cost of the product. Embedded systems

are often mass-produced, benefiting from economies of scale.

Personal digital assistants (PDAs) or handheld computers are generally considered

embedded devices because of the nature of their hardware design, even though they are more

expandable in software terms. This line of definition continues to blur as devices expand. With

the introduction of the OQO Model 2 with the Windows XP operating system and ports such as a

USB port — both features usually belong to "general purpose computers", — the line of

nomenclature blurs even more.

Physically, embedded systems ranges from portable devices such as digital watches and

MP3 players, to large stationary installations like traffic lights, factory controllers, or the systems

controlling nuclear power plants.

In terms of complexity embedded systems can range from very simple with a single

microcontroller chip, to very complex with multiple units, peripherals and networks mounted

inside a large chassis or enclosure.

Examples of

Embedded Systems:

Avionics, such as inertial guidance systems, flight control hardware/software and other

integrated systems in aircraft and missiles

Cellular telephones and telephone switches

Engine controllers and antilock brake controllers for automobiles

Home automation products, such as thermostats, air conditioners, sprinklers, and security

monitoring systems

Handheld calculators

Handheld computers

Household appliances, including microwave ovens, washing machines, television sets,

DVD players and recorders

Medical equipment

Personal digital assistant

Videogame consoles

Computer peripherals such as routers and printers.

Industrial controllers for remote machine operation.

BLOCK DIAGRAM:

BLOCK DIAGRAM DESCRIPTION

Power Supply Section:

This section is meant for supplying Power to all the sections mentioned above. It

basically consists of a Transformer to step down the 230V ac to 9V ac followed by diodes. Here

diodes are used to rectify the ac to dc. After rectification the obtained rippled dc is filtered using

a capacitor Filter. A positive voltage regulator is used to regulate the obtained dc voltage.

Microcontroller Section:

This section forms the control unit of the whole project. This section basically consists

of a Microcontroller with its associated circuitry like Crystal with capacitors, Reset circuitry,

Pull up resistors (if needed) and so on. The Microcontroller forms the heart of the project

because it controls the devices being interfaced and communicates with the devices according to

the program being written.

Driver circuit:

L293d is to construct with transistors and Motor. It is used to rotate the device.

POWER SUPPLY

LCD

MEMS

MOTOR DRIVER

MOTORSMICRO

CONTROLLER UNIT(AT89S52)

VOICE IC

SPEAKER

MOTORS:

Motor is an output device; its speed will be varied according to the speed set by the

switches. The speed can be varied by varying the voltage given to the PWM converter (using

keypad). The speed of DC motor is directly proportional to armature voltage and inversely

proportional to flux. By maintaining the flux constant, the speed can be varied by varying the

armature voltage.

MEMS:

Accelerometers are acceleration sensors. An inertial mass suspended by springs is acted

upon by acceleration forces that cause the mass to be deflected from its initial position. This

deflection is converted to an electrical signal, which appears at the sensor output. The application

of MEMS technology to accelerometers is a relatively new development.

VOICE IC:

Here we can store or record our voice in the ic and we can play back that voice

LCD Display Section:

This section is basically meant to show up the status of the project. This project

makes use of Liquid Crystal Display to display / prompt for necessary information.

Hardware Components

Micro controller

LCD Display

Power Supply

MEMS

Voice IC

L293D

Hardware Components explanation:

AT89S52

8-bit Microcontroller with 8K Bytes

In-System Programmable Flash

Features

• Compatible with MCS-51® Products

• 8K Bytes of In-System Programmable (ISP) Flash Memory

– Endurance: 1000 Write/Erase Cycles

• 4.0V to 5.5V Operating Range

• Fully Static Operation: 0 Hz to 33 MHz

• Three-level Program Memory Lock

• 256 x 8-bit Internal RAM

• 32 Programmable I/O Lines

• Three 16-bit Timer/Counters

• Eight Interrupt Sources

• Full Duplex UART Serial Channel

• Low-power Idle and Power-down Modes

• Interrupt Recovery from Power-down Mode

• Watchdog Timer

• Dual Data Pointer

• Power-off Flag

Description

The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with 8K bytes of

in-system programmable Flash memory. The device is manufactured using Atmel’s high-density

nonvolatile memory technology and is compatible with the industry- standard 80C51 instruction

set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or

by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with in-

system programmable Flash on a monolithic chip, the Atmel AT89S52 is a powerful

microcontroller which provides a highly-flexible and cost-effective solution to many embedded

control applications. The AT89S52 provides the following standard features: 8K bytes of Flash,

256 bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bit timer/counters,

a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator,

and clock circuitry. In addition, the AT89S52 is designed with static logic for operation down to

zero frequency and supports two software selectable power saving modes. The Idle Mode stops

the CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue

functioning. The Power-down mode saves the RAM contents but freezes the oscillator, disabling

all other chip functions until the next interrupt or hardware reset.

Pin Description

VCC

Supply voltage.

GND

Ground.

Port 0

Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can sink eight

TTL inputs. When 1s are written to port 0 pins, the pins can be used as high impedance inputs.

Port 0 can also be configured to be the multiplexed low order address/data bus during accesses to

external program and data memory. In this mode, P0 has internal pullups. Port 0 also receives the

code bytes during Flash programming and outputs the code bytes during program verification.

External pullups are required during program verification.

Port 1

Port 1 is an 8-bit bidirectional I/O port with internal pullups. The Port 1 output buffers can

sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the

internal pullups and can be used as inputs. As inputs, Port 1 pins that are externally being pulled

low will source current (IIL) because of the internal pullups. In addition, P1.0 and P1.1 can be

configured to be the timer/counter 2 external count input (P1.0/T2) and the timer/counter 2

trigger input (P1.1/T2EX), respectively, as shown in the following table.

Port 1 also receives the low-order address bytes during Flash programming and verification.

Port 2

Port 2 is an 8-bit bidirectional I/O port with internal pullups. The Port 2 output buffers can

sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by the

internal pullups and can be used as inputs. As inputs, Port 2 pins that are externally being pulled

low will source current (IIL) because of the internal pullups. Port 2 emits the high-order address

byte during fetches from external program memory and during accesses to external data memory

that use 16-bit addresses (MOVX @ DPTR). In this application, Port 2 uses strong internal pull-

ups when emitting 1s. During accesses to external data memory that use 8-bit addresses (MOVX

@ RI), Port 2 emits the contents of the P2 Special Function Register. Port 2 also receives the

high-order address bits and some control signals during Flash programming and verification.

Port 3

Port 3 is an 8-bit bidirectional I/O port with internal pullups. The Port 3 output buffers can

sink/source four TTL inputs. When 1s are written to Port 3 pins, they are pulled high by the

internal pullups and can be used as inputs. As inputs, Port 3 pins that are externally being pulled

low will source current (IIL) because of the pullups. Port 3 also serves the functions of various

special features of the AT89S52, as shown in the following table. Port 3 also receives some

control signals for Flash programming and verification.

RST

Reset input. A high on this pin for two machine cycles while the oscillator is running resets the

device. This pin drives High for 96 oscillator periods after the Watchdog times out. The DISRTO

bit in SFR AUXR (address 8EH) can be used to disable this feature. In the default state of bit

DISRTO, the RESET HIGH out feature is enabled.

ALE/PROG

Address Latch Enable (ALE) is an output pulse for latching the low byte of the address during

accesses to external memory. This pin is also the program pulse input (PROG) during Flash

programming. In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator

frequency and may be used for external

timing or clocking purposes. Note, however, that one ALE pulse is skipped during each access to

external data memory. If desired, ALE operation can be disabled by setting bit 0 of SFR location

8EH. With the bit set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the

pin is weakly pulled high. Setting the ALE-disable bit has no effect if the microcontroller is in

external execution mode.

PSEN

Program Store Enable (PSEN) is the read strobe to external program memory. When the

AT89S52 is executing code from external program memory, PSEN is activated twice each

machine cycle, except that two PSEN activations are skipped during each access to external data

memory.

EA/VPP

External Access Enable. EA must be strapped to GND in order to enable the device to fetch code

from external program memory locations starting at 0000H up to FFFFH. Note, however, that if

lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC

for internal program executions. This pin also receives the 12-volt programming enable voltage

(VPP) during Flash programming.

XTAL1

Input to the inverting oscillator amplifier and input to the internal clock operating circuit.

XTAL2

Output from the inverting oscillator amplifier.

Table 1. AT89S52 SFR Map and Reset Values

Special Function Registers

A map of the on-chip memory area called the Special Function Register (SFR) space is shown in

Table 1.

Note that not all of the addresses are occupied, and unoccupied addresses may not be

implemented on the chip. Read accesses to these addresses will in general return random data,

and write accesses will have an indeterminate effect. User software should not write 1s to these

unlisted locations, since they may be used in future products to invoke new features. In that case,

the reset or inactive values of the new bits will always be 0.

Timer 2 Registers: Control and status bits are contained in registers T2CON (shown in Table 2)

and T2MOD (shown in Table 3) for Timer 2. The register pair (RCAP2H, RCAP2L) are the

Capture/Reload registers for Timer 2 in 16-bit capture mode or 16-bit auto-reload mode.

Interrupt Registers: The individual interrupt enable bits are in the IE register. Two priorities can

be set for each of the six interrupt sources in the IP register.

Dual Data Pointer Registers: To facilitate accessing both internal and external data memory, two

banks of 16-bit Data Pointer Registers are provided: DP0 at SFR address locations 82H-83H and

DP1 at 84H-85H. Bit DPS = 0 in SFR AUXR1 selects DP0 and DPS = 1 selects DP1. The user

should always initialize the DPS bit to the appropriate value before accessing the respective Data

Pointer Register.

Power Off Flag: The Power Off Flag (POF) is located at bit 4 (PCON.4) in the PCON SFR. POF

is set to “1” during power up. It can be set and rest under software control and is not affected by

reset.

Memory Organization

MCS-51 devices have a separate address space for Program and Data Memory. Up to 64K bytes

each of external Program and Data Memory can be addressed.

Program Memory

If the EA pin is connected to GND, all program fetches are directed to external memory. On the

AT89S52, if EA is connected to VCC, program fetches to addresses 0000H through 1FFFH are

directed to internal memory and fetches to addresses 2000H through FFFFH are to external

memory.

Data Memory

The AT89S52 implements 256 bytes of on-chip RAM. The upper 128 bytes occupy a parallel

address space to the Special Function Registers. This means that the upper 128 bytes have the

same addresses as the SFR space but are physically separate from SFR space. When an

instruction accesses an internal location above

address 7FH, the address mode used in the instruction specifies whether the CPU accesses the

upper 128 bytes of RAM or the SFR space. Instructions which use direct addressing access of the

SFR space. For example, the following direct addressing instruction accesses the SFR at location

0A0H (which is P2).

MOV 0A0H, #data

Instructions that use indirect addressing access the upper 128 bytes of RAM. For example, the

following indirect addressing instruction, where R0 contains 0A0H, accesses the data byte at

address 0A0H, rather than P2 (whose address is 0A0H).

MOV @R0, #data

Note that stack operations are examples of indirect addressing, so the upper 128 bytes of data

RAM are available as stack space.

Watchdog Timer

(One-time Enabled with Reset-out)

The WDT is intended as a recovery method in situations where the CPU may be subjected to

software upsets. The WDT consists of a 13-bit counter and the Watchdog Timer Reset

(WDTRST) SFR. The WDT is defaulted to disable from exiting reset. To enable the WDT, a

user must write 01EH and 0E1H in sequence to the WDTRST register (SFR location 0A6H).

When the WDT is enabled, it will increment every machine cycle while the oscillator is running.

The WDT timeout period is dependent on the external

clock frequency. There is no way to disable the WDT except through reset (either hardware reset

or WDT overflow reset). When WDT overflows, it will drive an output RESET HIGH pulse at

the RST pin.

Using the WDT

To enable the WDT, a user must write 01EH and 0E1H in sequence to the WDTRST register

(SFR location 0A6H). When the WDT is enabled, the user needs to service it by writing 01EH

and 0E1H to WDTRST to avoid a WDT overflow. The 13-bit counter overflows when it reaches

8191 (1FFFH), and this will reset the device. When the WDT is enabled, it will increment every

machine cycle while the oscillator is running. This means the user must reset the WDT at least

every 8191 machine cycles. To reset the WDT the user must write 01EH and 0E1H to WDTRST.

WDTRST is a write-only register. The WDT counter cannot

be read or written. When WDT overflows, it will generate an output RESET pulse at the RST

pin. The RESET pulse duration is 96xTOSC, where TOSC=1/FOSC. To make the best use of the

WDT, it should be serviced in those sections of code that will periodically be executed within the

time required to prevent a WDT reset.

WDT During Power-down and Idle

In Power-down mode the oscillator stops, which means the WDT also stops. While in Power-

down mode, the user does not need to service the WDT. There are two methods of exiting

Power-down mode: by a hardware reset or via a level-activated external interrupt which is

enabled prior to entering Power-down mode. When Power-down is exited with hardware reset,

servicing the WDT should occur as it normally does whenever the AT89S52 is reset. Exiting

Power-down with an interrupt is significantly different. The

interrupt is held low long enough for the oscillator to stabilize. When the interrupt is brought

high, the interrupt is serviced. To prevent the WDT from resetting the device while the interrupt

pin is held low, the WDT is not started until the interrupt is pulled high. It is suggested that the

WDT be reset during the interrupt service for the interrupt used to exit Power-down mode. To

ensure that the WDT does not overflow within a few states of exiting Power-down, it is best to

reset the WDT just before entering Power-down mode. Before going into the IDLE mode, the

WDIDLE bit in SFR AUXR is used to determine whether the WDT continues to count if

enabled. The WDT keeps counting during IDLE (WDIDLE bit = 0) as the default state. To

prevent the WDT from resetting the AT89S52 while in IDLE mode, the user

should always set up a timer that will periodically exit IDLE, service the WDT, and reenter

IDLE mode.

With WDIDLE bit enabled, the WDT will stop to count in IDLE mode and resumes the count

upon exit from IDLE.

UART

The UART in the AT89S52 operates the same way as the UART in the AT89C51 and

AT89C52..

Timer 0 and 1

Timer 0 and Timer 1 in the AT89S52 operate the same way as Timer 0 and Timer 1 in the

AT89C51 and AT89C52

Timer 2

Timer 2 is a 16-bit Timer/Counter that can operate as either a timer or an event counter. The type

of operation is selected by bit C/T2 in the SFR T2CON (shown in Table 2). Timer 2 has three

operating modes: capture, auto-reload (up or down counting), and baud rate generator. The

modes are selected by bits in T2CON, as shown in Table 3. Timer 2 consists of two 8-bit

registers, TH2 and TL2. In the Timer function, the TL2 register is incremented every machine

cycle. Since a machine cycle consists of 12 oscillator periods, the count rate is 1/12 of the

oscillator frequency.

In the Counter function, the register is incremented in response to a 1-to-0 transition at its

corresponding external input pin, T2. In this function, the external input is sampled during S5P2

of every machine cycle. When the samples show a high in one cycle and a low in the next cycle,

the count is incremented. The new count value appears in the register during S3P1 of the cycle

following the one in which the transition was detected. Since two machine cycles (24 oscillator

periods) are required to recognize a 1-to-0 transition,

the maximum count rate is 1/24 of the oscillator frequency. To ensure that a given level is

sampled at least

once before it changes, the level should be held for at least one full machine cycle.

Capture Mode

In the capture mode, two options are selected by bit EXEN2 in T2CON. If EXEN2 = 0, Timer 2

is a 16-bit timer or counter which upon overflow sets bit TF2 in T2CON. This bit can then be

used to generate an interrupt. If EXEN2 = 1, Timer 2 performs the same operation, but a 1- to-0

transition at external input T2EX also causes the current value in TH2 and TL2 to be captured

into RCAP2H and RCAP2L, respectively. In addition, the transition at T2EX causes bit EXF2 in

T2CON to be set. The EXF2 bit,

like TF2, can generate an interrupt. The capture mode is illustrated in Figure 5.

Auto-reload (Up or Down Counter)

Timer 2 can be programmed to count up or down when configured in its 16-bit auto-reload

mode. This feature is invoked by the DCEN (Down Counter Enable) bit located in the SFR

T2MOD (see Table 4). Upon reset, the DCEN bit is set to 0 so that timer 2 will default to count

up. When DCEN is set, Timer 2 can count up or down, depending on the value of the T2EX pin.

Figure 6 shows Timer 2 automatically counting up when DCEN=0. In this mode, two options are

selected by bit EXEN2 in T2CON. If EXEN2 = 0, Timer 2 counts up to 0FFFFH and then sets

the TF2 bit upon overflow. The overflow also causes the timer registers to be reloaded with the

16-bit value in RCAP2H and RCAP2L. The values in Timer in Capture ModeRCAP2H and

RCAP2L are preset by software. If EXEN2 = 1, a 16-bit reload can be triggered either by an

overflow or by a 1-to-0 transition at external input T2EX. This transition also sets the EXF2 bit.

Both the TF2 and EXF2 bits can generate an interrupt if enabled.

Setting the DCEN bit enables Timer 2 to count up or down, as shown in Figure 6. In this mode,

the T2EX pin controls the direction of the count. A logic 1 at T2EX makes Timer 2 count up.

The timer will overflow at 0FFFFH and set the TF2 bit. This overflow also causes the 16-bit

value in RCAP2H and RCAP2L to be reloaded into the timer registers, TH2 and TL2,

respectively. A logic 0 at T2EX makes Timer 2 count down. The timer underflows when TH2

and TL2 equal the values stored in RCAP2H and RCAP2L. The underflow sets the TF2 bit and

causes 0FFFFH to be reloaded into the timer registers. The EXF2 bit toggles whenever Timer 2

overflows or underflows and can be used as a 17th bit of resolution. In this operating mode,

EXF2 does not flag an interrupt.

Baud Rate Generator

Timer 2 is selected as the baud rate generator by setting TCLK and/or RCLK in T2CON (Table

2). Note that the baud rates for transmit and receive can be different if Timer 2 is used for the

receiver or transmitter and Timer 1 is used for the other function. Setting RCLK and/or TCLK

puts Timer 2 into its baud rate generator mode, as shown in Figure 8. The baud rate generator

mode is similar to the auto-reload

mode, in that a rollover in TH2 causes the Timer 2 registers to be reloaded with the 16-bit value

in registers RCAP2H and RCAP2L, which are preset by software. The baud rates in Modes 1 and

3 are determined by Timer 2’s overflow rate according to the following equation.

The Timer can be configured for either timer or counter operation. In most applications, it is

configured for timer operation (CP/T2 = 0). The timer operation is different for Timer 2 when it

is used as a baud rate generator. Normally, as a timer, it increments every machine cycle (at 1/12

the oscillator frequency). As a baud rate generator, however, it increments every state time (at

1/2 the oscillator frequency). The baud rate formula is given below.

where (RCAP2H, RCAP2L) is the content of RCAP2H and RCAP2L taken as a 16-bit unsigned

integer.

Timer 2 as a baud rate generator is shown in Figure 8. This figure is valid only if RCLK or

TCLK = 1 in T2CON. Note that a rollover in TH2 does not set TF2 and will not generate an

interrupt. Note too, that if EXEN2 is set, a 1-to-0 transition in T2EX will set EXF2 but will not

cause a reload from (RCAP2H, RCAP2L) to (TH2, TL2). Thus, when Timer 2 is in use as a baud

rate generator, T2EX can be used as

an extra external interrupt. Note that when Timer 2 is running (TR2 = 1) as a timer in the baud

rate generator mode, TH2 or TL2 should not be read from or written to. Under these conditions,

the Timer is

incremented every state time, and the results of a read or write may not be accurate. The RCAP2

registers may be read but should not be written to, because a write might overlap a reload and

cause write and/or reload errors. The timer should be turned off (clear TR2) before accessing the

Timer 2 or RCAP2 registers.

Programmable Clock Out

A 50% duty cycle clock can be programmed to come out on P1.0, as shown in Figure 9. This pin,

besides being a regular I/O pin, has two alternate functions. It can be programmed to input the

external clock for Timer/Counter 2 or to output a 50% duty cycle clock ranging from 61 Hz to 4

MHz at a 16 MHz operating frequency. To configure the Timer/Counter 2 as a clock generator,

bit C/T2 (T2CON.1) must be cleared and bit T2OE (T2MOD.1) must be set. Bit TR2 (T2CON.2)

starts and stops the timer. The clock-out frequency depends on the oscillator frequency and the

reload value of Timer 2 capture registers (RCAP2H, RCAP2L), as shown in the following

equation.

In the clock-out mode, Timer 2 roll-overs will not generate an interrupt. This behavior is similar

to when Timer 2 is used as a baud-rate generator. It is possible to use Timer 2 as a baud-rate

generator and a clock generator simultaneously. Note, however, that the baud-rate and clock-out

frequencies cannot be determined independently from one another since they both use RCAP2H

and RCAP2L.

Interrupts

The AT89S52 has a total of six interrupt vectors: two external interrupts (INT0 and INT1), three

timer interrupts (Timers 0, 1, and 2), and the serial port interrupt. These interrupts are all shown

in Figure 10.

Each of these interrupt sources can be individually enabled or disabled by setting or clearing a bit

in Special Function Register IE. IE also contains a global disable bit, EA, which disables all

interrupts at once.

Note that Table 5 shows that bit position IE.6 is unimplemented. In the AT89S52, bit position

IE.5 is also unimplemented. User software should not write 1s to these bit positions, since they

may be used in future AT89 products. Timer 2 interrupt is generated by the logical OR of bits

TF2 and EXF2 in register T2CON. Neither of these flags is cleared by hardware when the

service routine is vectored to. In fact, the service routine may have to determine whether it was

TF2 or EXF2 that generated the interrupt, and that bit will have to be cleared in software. The

Timer 0 and Timer 1 flags, TF0 and TF1, are set at S5P2 of the cycle in which the timers

overflow. The values are then polled by the circuitry in the next cycle. However, the Timer 2

flag, TF2, is set at S2P2 and is polled in the same cycle in which the timer overflows.

Oscillator Characteristics

XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier that can be

configured for use as an on-chip oscillator, as shown in Figure 11. Either a quartz crystal or

ceramic resonator may be used. To drive the device from an external clock source, XTAL2

should be left unconnected while XTAL1 is driven, as shown in Figure 12. There are no

requirements on the duty cycle of the external clock signal, since the input to the internal

clocking circuitry is through a divide-by-two flip-flop, but minimum and maximum voltage high

and low time specifications must be observed.

Idle Mode

In idle mode, the CPU puts itself to sleep while all the onchip peripherals remain active. The

mode is invoked by software. The content of the on-chip RAM and all the special functions

registers remain unchanged during this mode. The idle mode can be terminated by any enabled

interrupt or by a hardware reset. Note that when idle mode is terminated by a hardware reset, the

device normally resumes program execution from where it left off, up to two machine cycles

before the internal reset algorithm takes control. On-chip hardware inhibits access to internal

RAM in this event, but access to the port pins is not inhibited. To eliminate the possibility of an

unexpected write to a port pin when idle mode is terminated by a reset, the instruction following

the one that invokes idle mode should not write to a port pin or to external memory.

Power-down Mode

In the Power-down mode, the oscillator is stopped, and the instruction that invokes Power-down

is the last instruction executed. The on-chip RAM and Special Function Registers retain their

values until the Power-down mode is terminated. Exit from Power-down mode can be initiated

either by a hardware reset or by an enabled external interrupt. Reset redefines the SFRs but does

not change the on-chip RAM. The reset should not be activated before VCC is restored to its

normal operating level and must be held active long enough to allow the oscillator to restart and

stabilize.

Figure 11. Oscillator Connections

Program Memory Lock Bits

The AT89S52 has three lock bits that can be left unprogrammed (U) or can be programmed (P)

to obtain the additional features listed in the following table.

When lock bit 1 is programmed, the logic level at the EA pin is sampled and latched during reset.

If the device is powered up without a reset, the latch initializes to a random value and holds that

value until reset is activated. The latched value of EA must agree with the current logic level at

that pin in order for the device to function properly.

Programming the Flash – Parallel Mode

The AT89S52 is shipped with the on-chip Flash memory array ready to be programmed. The

programming interface needs a high-voltage (12-volt) program enable signal and is compatible

with conventional third-party Flash or EPROM programmers. The AT89S52 code memory array

is programmed byte-bybyte.

Programming Algorithm: Before programming the AT89S52, the address, data, and control

signals should be set up according to the Flash programming mode table and Figures 13 and 14.

To program the AT89S52, take the following

steps:

1. Input the desired memory location on the address lines.

2. Input the appropriate data byte on the data lines.

3. Activate the correct combination of control signals.

4. Raise EA/VPP to 12V.

5. Pulse ALE/PROG once to program a byte in the Flash array or the lock bits. The byte-write

cycle is

self-timed and typically takes no more than 50 μs. Repeat steps 1 through 5, changing the

address

and data for the entire array or until the end of the object file is reached.

Data Polling: The AT89S52 features Data Polling to indicate the end of a byte write cycle.

During a write cycle, an attempted read of the last byte written will result in the complement of

the written data on P0.7. Once the write cycle has been completed, true data is valid on all

outputs, and the next cycle may begin. Data Polling may begin any time after a write cycle has

been initiated.

Ready/Busy: The progress of byte programming can also be monitored by the RDY/BSY output

signal. P3.0 is pulled low after ALE goes high during programming to indicate BUSY. P3.0 is

pulled high again when programming is done to indicate READY.

Program Verify: If lock bits LB1 and LB2 have not been programmed, the programmed code

data can be read back via the address and data lines for verification. The status of the individual

lock bits can be verified directly by reading them back.

Reading the Signature Bytes: The signature bytes are read by the same procedure as a normal

verification of locations 000H, 100H, and 200H, except that P3.6 and P3.7 must be pulled to a

logic low. The values returned are as follows.

(000H) = 1EH indicates manufactured by Atmel

(100H) = 52H indicates 89S52

(200H) = 06H

Chip Erase: In the parallel programming mode, a chip erase operation is initiated by using the

proper combination of control signals and by pulsing ALE/PROG low for a duration of 200 ns -

500 ns.

In the serial programming mode, a chip erase operation is initiated by issuing the Chip Erase

instruction. In this mode, chip erase is self-timed and takes about 500 ms. During chip erase, a

serial read from any address location will return 00H at the data output.

Programming the Flash – Serial Mode

The Code memory array can be programmed using the serial ISP interface while RST is pulled to

VCC. The serial interface consists of pins SCK, MOSI (input) and MISO (output). After RST is

set high, the Programming Enable instruction needs to be executed first before other operations

can be executed. Before a reprogramming sequence can occur, a Chip Erase operation is

required. The Chip Erase operation turns the content of every memory location in the Code array

into FFH. Either an external system clock can be supplied at pin XTAL1 or a crystal needs to be

connected across pins XTAL1 and XTAL2. The maximum serial clock (SCK) frequency should

be less than 1/16 of the crystal frequency. With a 33 MHz oscillator clock, the maximum SCK

frequency is 2 MHz.

Serial Programming Algorithm

To program and verify the AT89S52 in the serial programming mode, the following sequence is

recommended:

1. Power-up sequence: Apply power between VCC and GND pins. Set RST pin to “H”.If a

crystal is not connected across pins XTAL1 and XTAL2, apply a 3 MHz to 33 MHz clock to

XTAL1 pin and wait for at least 10 milliseconds.

2. Enable serial programming by sending the Programming Enable serial instruction to pin

MOSI/P1.5. The frequency of the shift clock supplied at pin SCK/P1.7 needs to be less than the

CPU clock at XTAL1 divided by 16.

3. The Code array is programmed one byte at a time by supplying the address and data together

with the

appropriate Write instruction. The write cycle is selftimed and typically takes less than 1 ms at

5V.

4. Any memory location can be verified by using the Read instruction which returns the content

at the

selected address at serial output MISO/P1.6.

5. At the end of a programming session, RST can be set low to commence normal device

operation.

Power-off sequence (if needed):

Set XTAL1 to “L” (if a crystal is not used).

Set RST to “L”.

Turn VCC power off.

Data Polling: The Data Polling feature is also available in the serial mode. In this mode, during a

write cycle an attempted read of the last byte written will result in the complement of the MSB of

the serial output byte on MISO.

Serial Programming Instruction Set

The Instruction Set for Serial Programming follows a 4-byte protocol and is shown in Table 10.

Programming Interface – Parallel Mode

Every code byte in the Flash array can be programmed by using the appropriate combination of

control signals. The write operation cycle is self-timed and once initiated, will automatically time

itself to completion. All major programming vendors offer worldwide support for the Atmel

microcontroller series. Please contact your local programming vendor for the appropriate

software revision.

After Reset signal is high, SCK should be low for at least 64 system clocks before it goes high to

clock in the enable data bytes. No pulsing of Reset signal is necessary. SCK should be no faster

than 1/16 of the system clock at XTAL1. For Page Read/Write, the data always starts from byte

0 to 255. After the command byte and upper address byte are latched, each byte thereafter is

treated as data until all 256

bytes are shifted in/out. Then the next instruction will be ready to be decoded.

MEMS:

Introduction

Micro-Electro-Mechanical Systems (MEMS) is the integration of mechanical elements, sensors,

actuators, and electronics on a common silicon substrate through microfabrication technology.

While the electronics are fabricated using integrated circuit (IC) process sequences (e.g., CMOS,

Bipolar, or BICMOS processes), the micromechanical components are fabricated using

compatible "micromachining" processes that selectively etch away parts of the silicon wafer or

add new structural layers to form the mechanical and electromechanical devices.

MEMS promises to revolutionize nearly every product category by bringing together silicon-

based microelectronics with micromachining technology, making possible the realization of

complete systems-on-a-chip. MEMS is an enabling technology allowing the development of

smart products, augmenting the computational ability of microelectronics with the perception

and control capabilities of micro sensors and micro actuators and expanding the space of possible

designs and applications.

Microelectronic integrated circuits can be thought of as the "brains" of a system and MEMS

augments this decision-making capability with "eyes" and "arms", to allow Microsystems to

sense and control the environment. Sensors gather information from the environment through

measuring mechanical, thermal, biological, chemical, optical, and magnetic phenomena. The

electronics then process the information derived from the sensors and through some decision

making capability direct the actuators to respond by moving, positioning, regulating, pumping,

and filtering, thereby controlling the environment for some desired outcome or purpose. Because

MEMS devices are manufactured using batch fabrication techniques similar to those used for

integrated circuits, unprecedented levels of functionality, reliability, and sophistication can be

placed on a small silicon chip at a relatively low cost.

Microelectromechanical systems

A mite less than 1 mm on a MEMS device.

Microelectromechanical systems (MEMS) (also written as micro-electro-mechanical, or

MicroElectroMechanical) is the technology of the very small, and merges at the nano-scale into

nanoelectromechanical systems (NEMS) and nanotechnology. MEMS are also referred to as

micromachines (in Japan), or Micro Systems Technology - MST (in Europe). MEMS are separate

and distinct from the hypothetical vision of molecular nanotechnology or molecular electronics.

MEMS are made up of components between 1 to 100 micrometres in size (i.e. 0.001 to 0.1 mm)

and MEMS devices generally range in size from 20 micrometres (20 millionths of a metre) to a

millimetre. They usually consist of a central unit that processes data, the microprocessor and

several components that interact with the outside such as microsensors[1]. At these size scales, the

standard constructs of classical physics are not always useful. Due to MEMS' large surface area

to volume ratio, surface effects such as electrostatics and wetting dominate volume effects such

as inertia or thermal mass.

The potential of very small machines was appreciated long before the technology existed that

could make them—see, for example, Richard Feynman's famous 1959 lecture There's Plenty of

Room at the Bottom. MEMS became practical once they could be fabricated using modified

semiconductor device fabrication technologies, normally used to make electronics. These include

molding and plating, wet etching (KOH, TMAH) and dry etching (RIE and DRIE), electro

discharge machining (EDM), and other technologies capable of manufacturing very small

devices.

MEMS description

MEMS technology can be implemented using a number of different materials and manufacturing

techniques; the choice of which will depend on the device being created and the market sector in

which it has to operate.

Materials for MEMS Manufacturing

Silicon

Silicon is the material used to create most integrated circuits used in consumer electronics in the

modern world. The economies of scale, ready availability of cheap high-quality materials and

ability to incorporate electronic functionality make silicon attractive for a wide variety of MEMS

applications. Silicon also has significant advantages engendered through its material properties.

In single crystal form, silicon is an almost perfect Hookean material, meaning that when it is

flexed there is virtually no hysteresis and hence almost no energy dissipation. As well as making

for highly repeatable motion, this also makes silicon very reliable as it suffers very little fatigue

and can have service lifetimes in the range of billions to trillions of cycles without breaking. The

basic techniques for producing all silicon based MEMS devices are deposition of material layers,

patterning of these layers by photolithography and then etching to produce the required shapes.

Polymers

Even though the electronics industry provides an economy of scale for the silicon industry,

crystalline silicon is still a complex and relatively expensive material to produce. Polymers on

the other hand can be produced in huge volumes, with a great variety of material characteristics.

MEMS devices can be made from polymers by processes such as injection molding, embossing

or stereolithography and are especially well suited to microfluidic applications such as

disposable blood testing cartridges.

Metals

Metals can also be used to create MEMS elements. While metals do not have some of the

advantages displayed by silicon in terms of mechanical properties, when used within their

limitations, metals can exhibit very high degrees of reliability.

Metals can be deposited by electroplating, evaporation, and sputtering processes.

Commonly used metals include gold, nickel, aluminium, chromium, titanium, tungsten,

platinum, and silver.

MEMS Basic Processes

This chart is not complete:

          Basic Process   

  Deposition    Patterning     Etching

Deposition processes

One of the basic building blocks in MEMS processing is the ability to deposit thin films of

material with a thickness anywhere between a few nanometres to about 100 micrometres.

Physical Deposition

There is a type of physical deposition.

Physical Vapor Deposition (PVD)

Sputtering

Evaporation

Chemical Deposition

There are 2 types of chemical deposition.

Chemical Vapor Deposition

LPCVD : Low Pressure CVD PECVD : Plasma Enhanced CVD

Thermal Oxidation

Patterning

Patterning in MEMS is the transfer of a pattern into a material.

Lithography

Lithography in MEMS context is typically the transfer of a pattern into a photosensitive material

by selective exposure to a radiation source such as light. A photosensitive material is a material

that experiences a change in its physical properties when exposed to a radiation source. If a

photosensitive material is selectively exposed to radiation (e.g. by masking some of the

radiation) the pattern of the radiation on the material is transferred to the material exposed, as the

properties of the exposed and unexposed regions differs.

This exposed region can then be removed or treated providing a mask for the underlying

substrate. Photolithography is typically used with metal or other thin film deposition, wet and dry

etching.

Photolithography

Electron Beam Lithography

Ion Beam Lithography

X-ray Lithography

Diamond Patterning

Etching processes

There are two basic categories of etching processes: wet and dry etching. In the former, the

material is dissolved when immersed in a chemical solution. In the latter, the material is

sputtered or dissolved using reactive ions or a vapor phase etchant. See Williams and Muller [2] or

Kovacs, Maluf and Peterson[3] for a somewhat dated overview of MEMS etching technologies.

1. Wet etching

Main article: Wet etching

Wet chemical etching consists in a selective removal of material by dipping a substrate into a

solution that can dissolve it. Due to the chemical nature of this etching process, a good selectivity

can often be obtained, which means that the etching rate of the target material is considerably

higher than that of the mask material if selected carefully.

2. Isotropic etching

Etching progresses at the same speed in all directions. Long and narrow holes in a mask will

produce v-shaped grooves in the silicon. The surface of these grooves can be atomically smooth

if the etch is carried out correctly, with dimensions and angles being extremely accurate.

3. Anisotropic etching

Some single crystal materials, such as silicon, will have different etching rates depending on the

crystallographic orientation of the substrate. This is known as anisotropic etching and one of the

most common examples is the etching of silicon in KOH (potassium hydroxide), where Si <111>

planes etch approximately 100 times slower than other planes (crystallographic orientations).

Therefore, etching a rectangular hole in a (100)-Si wafer will result in a pyramid shaped etch pit

with 54.7° walls, instead of a hole with curved sidewalls as it would be the case for isotropic

etching.

4. Electrochemical etching

Electrochemical etching (ECE) for dopant-selective removal of silicon is a common method to

automate and to selectively control etching. An active p-n diode junction is required, and either

type of dopant can be the etch-resistant ("etch-stop") material. Boron is the most common etch-

stop dopant. In combination with wet anisotropic etching as described above, ECE has been used

successfully for controlling silicon diaphragm thickness in commercial piezoresistive silicon

pressure sensors. Selectively doped regions can be created either by implantation, diffusion, or

epitaxial deposition of silicon.

5. Xenon difluoride etching

Xenon difluoride (XeF2) is a dry vapor phase isotropic etch for silicon originally applied for

MEMS in 1995 at University of California, Los Angeles[4][5]. Primarily used for releasing metal

and dielectric structures by undercutting silicon, XeF2 has the advantage of a stiction-free release

unlike wet etchants. Its etch selectivity to silicon is very high, allowing it to work with photo

resist, SiO2, silicon nitride, and various metals for masking. Its reaction to silicon is "plasma

less", is purely chemical and spontaneous and is often operated in pulsed mode. Models of the

etching action are available[6], and university laboratories and various commercial tools offer

solutions using this approach.

6.HF Etching

Hydrofluoric acid is commonly used as an aqueous etchant for silicon dioxide (SiO2, aka BOX

for SOI). HF are usually in 49% concentrated form, 5:1, 10:1 or 20:1 BOE (Buffered Oxide

Etchant) or BHF (Buffered HF). They were first used in medieval times for glass etching. It was

used in IC fabrication for patterning the gate oxide until the process step was replaced by RIE.

HF is considered one of the more dangerous acids in the clean room. It penetrates the skin upon

contact and it diffuses straight to the bone. Therefore the damage will not be felt until it is too

late.

7. Reactive ion etching (RIE)

Main article: Reactive ion etching

In reactive ion etching (RIE), the substrate is placed inside a reactor in which several gases are

introduced. A plasma is struck in the gas mixture using an RF power source, breaking the gas

molecules into ions. The ions are accelerated towards, and react with, the surface of the material

being etched, forming another gaseous material. This is known as the chemical part of reactive

ion etching. There is also a physical part which is similar in nature to the sputtering deposition

process. If the ions have high enough energy, they can knock atoms out of the material to be

etched without a chemical reaction. It is a very complex task to develop dry etches processes that

balance chemical and physical etching, since there are many parameters to adjust. By changing

the balance it is possible to influence the anisotropy of the etching, since the chemical part is

isotropic and the physical part highly anisotropic the combination can form sidewalls that have

shapes from rounded to vertical. RIE can be deep and its name will be Deep RIE or DRIE Deep

reactive ion etching (DRIE)

Main article: Deep reactive ion etching

A special subclass of RIE which continues to grow rapidly in popularity is deep RIE (DRIE). In

this process, etch depths of hundreds of micrometres can be achieved with almost vertical

sidewalls. The primary technology is based on the so-called "Bosch process" [7], named after the

German company Robert Bosch which filed the original patent, where two different gas

compositions are alternated in the reactor. Currently there are two variations of the DRIE. The

first variation consists of three distinct steps (the Bosch Process as used in the UNAXIS tool)

while the second variation only consists of two steps (ASE used in the STS tool). In the 1st

Variation, the etch cycle is as follows: (i) SF6 isotropic etch; (ii) C4F8 passivation; (iii) SF6

anisoptropic etch for floor cleaning. In the 2nd variation, steps (i) and (iii) are combined.

Both variations operate similarly. The C4F8 creates a polymer on the surface of the substrate, and

the second gas composition (SF6 and O2) etches the substrate. The polymer is immediately

sputtered away by the physical part of the etching, but only on the horizontal surfaces and not the

sidewalls. Since the polymer only dissolves very slowly in the chemical part of the etching, it

builds up on the sidewalls and protects them from etching. As a result, etching aspect ratios of 50

to 1 can be achieved. The process can easily be used to etch completely through a silicon

substrate, and etch rates are 3-6 times higher than wet etching.

8. Dry Etching

9. Vapor Etching

10. Plasma Etching

11. Sputtering

Fabrication Technologies

The three characteristic features of MEMS fabrication technologies are miniaturization,

multiplicity, and microelectronics. Miniaturization enables the production of compact, quick-

response devices. Multiplicity refers to the batch fabrication inherent in semiconductor

processing, which allows thousands or millions of components to be easily and concurrently

fabricated. Microelectronics provides the intelligence to MEMS and allows the monolithic

merger of sensors, actuators, and logic to build closed-loop feedback components and systems.

The successful miniaturization and multiplicity of traditional electronics systems would not have

been possible without IC fabrication technology. Therefore, IC fabrication technology, or

microfabrication, has so far been the primary enabling technology for the development of

MEMS. Microfabrication provides a powerful tool for batch processing and miniaturization of

mechanical systems into a dimensional domain not accessible by conventional (machining)

techniques. Furthermore, microfabrication provides an opportunity for integration of mechanical

systems with electronics to develop high-performance closed-loop-controlled MEMS.

Advances in IC technology in the last decade have brought about corresponding progress in

MEMS fabrication processes. Manufacturing processes allow for the monolithic integration of

microelectromechanical structures with driving, controlling, and signal-processing electronics.

This integration promises to improve the performance of micromechanical devices as well as

reduce the cost of manufacturing, packaging, and instrumenting these devices .

A. IC Fabrication

Any discussion of MEMS requires a basic understanding of IC fabrication technology, or

microfabrication, the primary enabling technology for the development of MEMS. The major

steps in IC fabrication technology are film growth, doping, lithography, etching, dicing, and

packaging.

Film growth: Usually, a polished Si wafer is used as the substrate, on which a thin film is grown.

The film, which may be epitaxial Si, SiO2, silicon nitride (Si3N4), polycrystalline Si

(polysilicon), or metal, is used to build both active or passive components and interconnections

between circuits.

Doping: To modulate the properties of the device layer, a low and controllable level of an atomic

impurity may be introduced into the layer by thermal diffusion or ion implantation.

Lithography: A pattern on a mask is then transferred to the film by means of a photosensitive

(i.e., light sensitive) chemical known as a photoresist. The process of pattern generation and

transfer is called photolithography. A typical mask consists of a glass plate coated with a

patterned chromium (Cr) film.

Etching: Next is the selective removal of unwanted regions of a film or substrate for pattern

delineation. Wet chemical etching or dry etching may be used. Etch-mask materials are used at

various stages in the removal process to selectively prevent those portions of the material from

being etched. These materials include SiO2, Si3N4, and hard-baked photoresist.

Dicing: The finished wafer is sawed or machined into small squares, or dice, from which

electronic components can be made.

Packaging: The individual sections are then packaged, a process that involves physically

locating, connecting, and protecting a device or component. MEMS design is strongly coupled to

the packaging requirements, which in turn are dictated by the application environment.

B. Bulk Micromachining and Wafer Bonding

Bulk micromachining is an extension of IC technology for the fabrication of 3D structures. Bulk

micromachining of Si uses wet- and dry-etching techniques in conjunction with etch masks and

etch stops to sculpt micromechanical devices from the Si substrate. The two key capabilities that

make bulk micromachining a viable technology are:

1) Anisotropic etchants of Si, such as ethylene-diamine and pyrocatechol (EDP), potassium

hydroxide (KOH), and hydrazine (N2H4). These preferentially etch single crystal Si along given

crystal planes.

2) Etch masks and etch-stop techniques that can be used with Si anisotropic etchants to

selectively prevent regions of Si from being etched. Good etch masks are provided by SiO2 and

Si3N4, and some metallic thin films such as Cr and Au (gold).

A drawback of wet anisotropic etching is that the microstructure geometry is defined by the

internal crystalline structure of the substrate. Consequently, fabricating multiple, interconnected

micromechanical structures of free-form geometry is often difficult or impossible. Two

additional processing techniques have extended the range of traditional bulk micromachining

technology: deep anisotropic dry etching and wafer bonding. Reactive gas plasmas can perform

deep anisotropic dry etching of Si wafers, up to a depth of a few hundred microns, while

maintaining smooth vertical sidewall profiles. The other technology, wafer bonding, permits a Si

substrate to be attached to another substrate, typically Si or glass. Used in combination,

anisotropic etching and wafer bonding techniques can construct 3D complex microstructures

such as microvalves and micropumps .

C. Surface Micromachining

Surface micromachining enables the fabrication of complex multicomponent integrated

micromechanical structures that would not be possible with traditional bulk micromachining.

This technique encases specific structural parts of a device in layers of a sacrificial material

during the fabrication process. The substrate wafer is used primarily as a mechanical support on

which multiple alternating layers of structural and sacrificial material are deposited and patterned

to realize micromechanical structures. The sacrificial material is then dissolved in a chemical

etchant that does not attack the structural parts. The most widely used surface micromachining

technique, polysilicon surface micromachining, uses SiO2 as the sacrificial material and

polysilicon as the structural material.

At the University of Wisconsin at Madison, polysilicon surface micromachining research started

in the early 1980s in an effort to create high-precision micro pressure sensors. The control of the

internal stresses of a thin film is important for the fabrication of microelectromechanical

structures. The microelectronic fabrication industry typically grows polysilicon, silicon nitride,

and silicon dioxide films using recipes that minimize time. Unfortunately, a deposition process

that is optimized to speed does not always create a low internal stress film. In fact, most of these

films have internal stresses that are highly compressive (tending to contract). A freestanding

plate of highly compressive polysilicon that is held at all its edges will buckle (i.e., collapse or

give way). This is highly undesirable. The solution is to modify the film deposition process to

control the internal stress by making it stress-free or slightly tensile.

One way to do this is to dope the film with boron, phosphorus, or arsenic. However, a doped

polysilicon film is conductive, and this property may interfere with the mechanical devices

incorporated electronics. Another problem with doped polysilicon is that it is roughened by

hydrofluoric acid (HF), which is commonly used to free sections of the final mechanical device

from the substrate. Rough polysilicon has different mechanical properties than smooth

polysilicon. Therefore, the amount of roughening must be taken into account when designing the

mechanical parts of the micro device.

A better way to control the stress in polysilicon is through post annealing, which involves the

deposition of pure, fine-grained, compressive (i.e., can be compressed) polysilicon. Annealing

the polysilicon after deposition at elevated temperatures can change the film to be stress-free or

tensile. The annealing temperature sets the film's final stress. After this, electronics can then be

incorporated into polysilicon films through selective doping, and hydrofluoric acid will not

change the mechanical properties of the material [16].

Deposition temperature and the film's silicon to nitride ratio can control the stress of a silicon

nitride (Si3N4) film. The films can be deposited in compression, stress-free, or in tension [6].

Deposition temperature and post annealing can control silicon dioxide (SiO2) film stress.

Because it is difficult to control the stress of SiO2 accurately, SiO2 is typically not used as a

mechanical material by itself, but as electronic isolation or as a sacrificial layer under

polysilicon.

D. Micromolding

In the micromolding process, microstructures are fabricated using molds to define the deposition

of the structural layer. The structural material is deposited only in those areas constituting the

microdevice structure, in contrast to bulk and surface micromachining, which feature blanket

deposition of the structural material followed by etching to realize the final device geometry.

After the structural layer deposition, the mold is dissolved in a chemical etchant that does not

attack the structural material. One of the most prominent micromolding processes is the LIGA

process. LIGA is a German acronym standing for lithographie, galvanoformung, und abformung

(lithography, electroplating, and molding). This process can be used for the manufacture of high-

aspect-ratio 3D microstructures in a wide variety of materials, such as metals, polymers,

ceramics, and glasses. Photosensitive polyimides are also used for fabricating plating molds. The

photolithography process is similar to conventional photolithography, except that polyimide

works as a negative resist

Applications

microelectromechanical systems chip, sometimes called "lab on a chip"

In one viewpoint MEMS application is categorized by type of use.

Sensor

Actuator

Structure

In another view point mems applications are categorized by the field of application(Commercial

applications include):

Inkjet printers , which use piezoelectrics or thermal bubble ejection to deposit ink on

paper.

Accelerometers in modern cars for a large number of purposes including airbag

deployment in collisions.

Accelerometers in consumer electronics devices such as game controllers (Nintendo

Wii), personal media players / cell phones (Apple iPhone, various Nokia mobile phone

models, various HTC PDA models)[9] and a number of Digital Cameras (various Canon

Digital IXUS models). Also used in PCs to park the hard disk head when free-fall is

detected, to prevent damage and data loss.

MEMS gyroscopes used in modern cars and other applications to detect yaw; e.g. to

deploy a roll over bar or trigger dynamic stability control.

Silicon pressure sensors e.g. car tire pressure sensors, and disposable blood pressure

sensors.

Displays e.g. the DMD chip in a projector based on DLP technology has on its surface

several hundred thousand micromirrors.

Optical switching technology which is used for switching technology and alignment for

data communications.

Bio-MEMS applications in medical and health related technologies from Lab-On-Chip to

MicroTotalAnalysis (biosensor, chemosensor).

Interferometric modulator display (IMOD) applications in consumer electronics

(primarily displays for mobile devices). Used to create interferometric modulation -

reflective display technology as found in mirasol displays.

Companies with strong MEMS programs come in many sizes. The larger firms specialize in

manufacturing high volume inexpensive components or packaged solutions for end markets such

as automobiles, biomedical, and electronics. The successful small firms provide value in

innovative solutions and absorb the expense of custom fabrication with high sales margins. In

addition, both large and small companies work in R&D to explore MEMS technology.

. Mems accelerometer:

WHAT IS AN ACCELEROMETER?

An accelerometer is an instrument for measuring acceleration, detecting and measuring

vibrations, or for measuring acceleration due to gravity (inclination). Accelerometers can be used

to measure vibration on vehicles, machines, buildings, process control systems and safety

installations. They can also be used to measure seismic activity, inclination, machine vibration,

dynamic distance and speed with or without the influence of gravity.

HOW DOES AN ACCELEROMETER WORK?

Used for calculating acceleration and measuring vibrations, the accelerometer is capable of

detecting even the slightest movements, from the tilting of a building to smallest vibration

caused by a musical instrument. Inside the accelerometer sensor minute structures are present

that produces electrical charges if the sensor experiences any movement.

Accelerometers need to be placed on the surface of the object in order to determine the

vibrations. It is not capable of work in isolation or apart from the object it is required to assess, it

must be firmly attached to the object in order to give precise readings.

KINDS OF ACCELEROMETER

The two kinds of basic accelerometers are:

1. ANALOG ACCELEROMETER

At times Inputs and output readings also matter especially when it comes to determining the kind

of accelerometer that needs to be placed on a certain object. If the output is digital then a digital

accelerometer must be placed and vice versa. The main feature of this accelerometer is that the

output tends to change when there is even a slight change in the input.

The most common type of this accelerometer is used in airbags of automobiles, to note the

sudden drop in the speed of the vehicle and to trigger the airbag release. Even laptops are now

being equipped with accelerometers in order to protect the hard drive against any physical

dangers, caused mainly due to accidental drops.

2. DIGITAL ACCELEROMETER

The digital accelerometer is more sophisticated than the analog. Here the amount of high voltage

time is proportional to the acceleration. One of its major advantages is that it is more stable and

produces a direct output signal. Accelerometers are now also used in aerospace and many

military applications, such as missile launch, weapon fire system, rocket deployment etc. Many a

times these accelerometers are used to protect fragile equipment during cargo transportation, and

report any strain that might cause a possible damage. Some companies have also managed to

develop a wireless 3-axis accelerometers which are not only low in cost but are also shock

durable. This 3-axis accelerometer has sensors that are used to protect mobiles and music

players. Also these sensors are used in some of the devices used for traffic navigation and

control.

PIEZOELECTRIC SENSOR

Depending upon the kind of work, the accelerometers vary in the way they are prepared and how

they work. Some accelerometers use piezoelectricity, these are man-made. In such

accelerometers the acceleration is calculated based upon the charges derived from the

microscopic crystalline structures when they are accelerated due to motion.

MEMS ACCELEROMETER

Another kind works with the capacitance and the changes initiated within it as a result of some

accelerative force. This technology is used from automotive industry to agriculture industry and

from NASA to military researches and operations.

STRAIN GAUGE

This device is used to measure strain in an object, which is detected by a foil strain element. If

the object, to which the gauge is attached is some how deformed that creates electrical charges

and is known as the gauge factor.

ACCELEROMETER IS USED IN:

AUTOMOTIVE INDUSTRY

Due to high demand and wide spread use of accelerometers in the automotive industry and new

hi-tech technology, these sensors are now light weight and are available at low cost and reduced

prices.

MICROPHONES

Microphones also carry accelerometers. That is how they are able to detect the minute

frequencies.

ROBOTICS

The forces that can cause vibrations which are detected by the accelerometer can be static,

dynamic or gravitational. Certain accelerometers are rated G. G stands for Gravity. Such

accelerometers are used mostly in robotics. They are more sensitive to motion and can be

triggered at the slightest changes in gravitational pulls.

Accelerometers

Accelerometers are acceleration sensors. An inertial mass suspended by springs is acted upon by

acceleration forces that cause the mass to be deflected from its initial position. This deflection is

converted to an electrical signal, which appears at the sensor output. The application of MEMS

technology to accelerometers is a relatively new development.

One such accelerometer design is discussed by DeVoe and Pisano (2001) [8]. It is a surface

micromachined piezoelectric accelerometer employing a zinc oxide (ZnO) active piezoelectric

film. The design is a simple cantilever structure, in which the cantilever beam serves

simultaneously as proof mass and sensing element. One of the fabrication approaches developed

is a sacrificial oxide process based on polysilicon surface micromachining, with the addition of a

piezoelectric layer atop the polysilicon film. In the sacrificial oxide process, a passivation layer

of silicon dioxide and low-stress silicon nitride is deposited on a bare silicon wafer, followed by

0.5 micron of liquid phase chemical vapor deposited (LPCVD) phosphorous-doped polysilicon.

Then, a 2.0-micron layer of phosphosilicate glass (PSG) is deposited by LPCVD and patterned to

define regions where the accelerometer structure will be anchored to the substrate. The PSG film

acts as a sacrificial layer that is selectively etched at the end to free the mechanical structures. A

second layer of 2.0-micron-thick phosphorus-doped polysilicon is deposited via LPCVD on top

of the PSG, and patterned by plasma etching to define the mechanical accelerometer structure.

This layer also acts as the lower electrode for the sensing film. A thin layer of silicon nitride is

next deposited by LPCVD, and acts as a stress-compensation layer for balancing the highly

compressive residual stresses in the ZnO film. By varying the thickness of the Si3N4 layer, the

accelerometer structure may be tuned to control bending effects resulting from the stress gradient

through the device thickness. A ZnO layer is then deposited on the order of 0.5 micron, followed

by sputtering of a 0.2-micron layer of platinum (Pt) deposited to form the upper electrode. A

rapid thermal anneal is performed to reduce residual stresses in the sensing film. Afterwards, the

Pt, Si3N4, and ZnO layers are patterned in a single ion milling etch step, and the devices are then

released by passivating the ZnO film with photoresist, and immersing the wafer in buffered

hydrofluoric acid, which removes the sacrificial PSG layer .

APR 9600 RE-Recording Voice IC

Single-chip Voice Recording & Playback Device

60- Second Duration

1 Features :

• Single-chip, high-quality voice recording & playback solution

- No external ICs required

- Minimum external components

• Non-volatile Flash memory technology

- No battery backup required

• User-Selectable messaging options

- Random access of multiple fixed-duration messages

- Sequential access of multiple variable-duration messages

• User-friendly, easy-to-use operation

- Programming & development systems not required

- Level-activated recording & edge-activated play back switches

• Low power consumption

- Operating current: 25 mA typical

- Standby current: 1 uA typical

- Automatic power-down

• Chip Enable pin for simple message expansion

2 General Description:

The APR9600 device offers true single-chip voice recording, non-volatile storage, and

playback capability for 40 to 60 seconds. The device supports both random and sequential access

of multiple messages. Sample rates are user- selectable, allowing designers to customize their

design for unique quality and storage time needs. Integrated output amplifier, microphone

amplifier, and AGC circuits greatly simplify system design. the device is ideal for use in portable

voice recorders, toys, and many other consumer and industrial applications.

APLUS integrated achieves these high levels of storage capability by using its proprietary

analog/multilevel storage technology implemented in an advanced Flash non-volatile memory

process, where each memory cell can store 256 voltage levels. This technology enables the

APR9600 device to reproduce voice signals in their natural form. It eliminates the need for

encoding and compression, which often introduce distortion.

Fig 12: The APR9600 DIP & SOP

3 Functional Description:

APR9600 block diagram is included in order to describe the device's internal architecture. At the

left hand side of the diagram are the analog inputs. A differential microphone amplifier,

including integrated AGC, is included on-chip for applications requiring use. The amplified

microphone signals fed into the device by connecting the ANA_OUT pin to the ANA_IN pin

through an external DC blocking capacitor. Recording can be fed directly into the ANA_IN pin

through a DC blocking capacitor, however, the connection between ANA_IN andANA OUT is

still required for playback. The next block encountered by the input signal is the internal anti-

aliasing filter. The filter automatically adjusts its response According to the sampling frequency

selected so Shannon’s Sampling Theorem is satisfied. After anti-aliasing filtering is

accomplished the signal is ready to be clocked into the memory array. This storage is

accomplished through a combination of the Sample and Hold circuit and the Analog Write/Read

circuit. Either the Internal Oscillator or an external clock source clocks these circuits. When

playback is desired the previously stored recording is retrieved from memory, low pass filtered,

and amplified as shown on the right hand side of the diagram. The signal can be heard by

connecting a speaker to the SP+ and SP- pins. Chip-wide management is accomplished through

the device control block shown in the upper right hand corner. Message management is provided

through the message control block represented in the lower center of the block diagram. More

detail on actual device application can be found in the Sample Application section. More detail

on sampling control can be found in the Sample Rate and Voice Quality section. More detail on

Message management and device control can be found in the Message Management section.

Fig 13: APR9600 Block Diagram

3.1 Message Management:

3.1.1 Message Management General Description

Playback and record operations are managed by on-chip circuitry. There are several available

messaging modes depending upon desired operation. These message modes determine message

management style, message length, and external parts count. Therefore, the designer must select

the appropriate operating mode before beginning the design. Operating modes do not affect voice

quality; for information on factors affecting quality refer to the Sampling Rate & Voice Quality

section. The device supports five message management modes (defined by the MSEL1, MSEL2

and /M8_OPTION pins shown in Figures 1 and 2):

Random access mode with 2, 4, or 8 fixed-duration messages Tape mode, with multiple variable-

duration messages, provides two options:

- Auto rewind

- Normal

Modes cannot be mixed. Switching of modes after the device has recorded an initial message is

not recommended. If modes are switched after an initial recording has been made some

unpredictable message fragments from the previous mode may remain present, and be audible on

playback, in the new mode. These fragments will disappear after a Record operation in the newly

selected mode. Table 1 defines the decoding necessary to choose the desired mode. An important

feature of the APR9600 Message management capabilities is the ability to audibly prompt the

user to change in the device's status through the use of "beeps" superimposed on the device's

output. This feature is enabled by asserting a logic high level on the BE pin.

3.1.2 Random Access Mode

Random access mode supports 2, 4, or 8 Message segments of fixed duration. As suggested

recording or playback can be made randomly in any of the elected messages. The length of each

message segment is the total recording length available (as defined by the selected sampling rate)

divided by the total number of segments enabled (as decoded in Table1). Random access mode

provides easy indexing to message segments.

3.1.2A Functional Description of Recording in Random Access Mode

On power up, the device is ready to record or playback in any of the enabled message segments.

To record,/CE must be set low to enable the device and /RE must be set low to enable recording.

You initiate recording by applying a low level on the message trigger pin that represents the

message segment you intend to use. The message trigger pins are labeled /M1_MESSAGE -

/M8_OPTION on pins 1-9 (excluding pin 7) for message segments 1-8 respectively. Note:

Message trigger pins of M1_MESSAGE,/M2_NEXT, /M7_END, and /M8_OPTION, have

expanded names to represent the different functionality that these pins assume in the other

modes. In random access mode these pins should be considered purely message trigger pins with

the same functionality as /M3, /M4, /M5, and /M6. For a more thorough explanation of the

functionality of device pins in different modes please refer to the pin description table that

appears later in this document. When actual recording begins the device responds with a single

beep (if the BE pin is high to enable the beep tone) at the speaker outputs to indicate that it has

started recording. Recording continues as long as the message pin stays low. The rising edge of

the same message trigger pin during record stops the recording operation (indicated with a single

beep). If the message trigger pin is held low beyond the end of the maximum allocated duration,

recording stops automatically (indicated with two beeps), regardless of the state of the message

trigger pin. The chip then enters low-power mode until the message trigger pin returns high.

After the message trigger pin returns to high, the chip enters standby mode. Any subsequent high

to low transition on the same message trigger pin will initiate recording from the beginning of

the same message segment. The entire previous message is then overwritten by the new message,

regardless of the duration of the new message. Transitions on any other message trigger pin or

the /RE pin during the record operation are ignored until after the device enters standby mode.

3.1.2B Functional Description of Playback Random Access Mode

On power up, the device is ready to record or playback, in any of the enabled message segments.

To playback,/CE must be set low to enable the device and /RE must be set high to disable

recording & enable playback. You initiate playback by applying a high to low edge on the

message trigger pin that represents the message segment you intend to playback. Playback will

continue until the end of the message is reached. If a high to low edge occurs on the same

message trigger pin during playback, playback of the current message stops immediately. If a

different message trigger pin pulses during playback, playback of the current message stops

immediately (indicated by one beep) and playback of the new message segment begins. A delay

equal to 8,400 cycles of he sample clock will be encountered before the device starts playing the

new message. If a message trigger pin is held low, the selected message is played back

repeatedly as long as the trigger pin stays low. A period of silence, of a duration equal to 8,400

cycles of the sampling clock, will be inserted during looping as an indicator to the user of the

transition between the end and the beginning of the message.

3.1.3 Tape Mode:

Tape mode manages messages sequentially much like traditional cassette tape recorders. Within

tape mode two options exist, auto rewind and normal. Auto rewind mode configures the device

to automatically rewind to the beginning of the message immediately following recording or

playback of the message. In tape mode, using either option, messages must be recorded or played

back sequentially, much like a traditional cassette tape recorder.

3.1.3.1A Function Description of Recording in Tape Mode using the Auto Rewind Option

On power up, the device is ready to record or playback, starting at the first address in the

memory array. To record, /CE must be set low to enable the device and /RE must be set low to

enable recording. A falling edge of the /M1_MESSAGE pin initiates voice recording (indicated

by one beep).A subsequent rising edge of the /M1_MESSAGE pin during recording stops the

recording (also indicated by one beep). If the M1_MESSAGE pin is held low beyond the end of

the available memory, recording will stop automatically (indicated by two beeps). The device

will then assert a logic low on the /M7_END pin until the /M1 Message pin is released.

The device returns to standby mode when the /M1_MESSAGE pin goes high gain. After

recording is finished the device will automatically rewind to the beginning of the most recently

recorded message and wait for the next user input. The auto rewind function is convenient

because it allows the user to immediately playback and review the message without the need to

rewind. However, caution must be practiced because a subsequent record operation will

overwrite the last recorded message unless the user remembers to pulse the /M2_Next pin in

order to increment the device past the current message.

A subsequent falling edge on the /M1_Message pin starts a new record operation, overwriting

the previously existing message. You can preserve the previously recorded message by using

the /M2_Next input to advance to the next available message segment. To perform this function,

the /M2_NEXT pin must be pulled low for at least 400 cycles of the sample clock. The auto

rewind mode allows the user to record over the just recorded message simply by initiating a

record sequence without first toggling the /M2_NEXT pin.

To record over any other message however requires a different sequence. You must pulse the

/CE pin low once to rewind the device to the beginning of the voice memory. The /M2_NEXT

pin must then be pulsed low for the specified number of times to move to the start of the message

you wish to overwrite. Upon arriving at the desired message a record sequence can be initiated to

overwrite the previously recorded material. After you overwrite the message it becomes the last

available message and all previously recorded messages following this message become

inaccessible. If during a record operation all of the available memory is used, the device will stop

recording automatically,(double beep) and set the /M7_END pin low for a duration equal to 1600

cycles of the sample clock. Playback can be initiated on this last message, but pulsing the

/M2_Next pin will put the device into an "overflow state". Once the device enters an overflow

state any subsequent pulsing of /M1_MESSAGE or /M2_NEXT will only result in a double beep

and setting of the /M7_END pin low for a duration equal to 400 cycles of the sample clock. To

proceed from this state the user must rewind the device to the beginning of the memory array.

This can be accomplished by toggling the /CE pin low or cycling power. All inputs, except

the /CE pin, are ignored during recording.

3.1.3.1B Function Description of Playback in Tape Mode using Auto Rewind Option

On power-up, the device is ready to record or playback, starting at the first address in the

memory array. Before you can begin playback, the /CE input must be set to low to enable the

device and /RE must be set to high to disable recording and enable playback. The first high to

low going pulse of the /M1_MESSAGE pin initiates playback from the beginning of the current

message; on power up the first message is the current message. When the /M1_MESSAGE pin

pulses low the second time, playback of the current Message stops immediately. When the

/M1_MESSAGE pin pulses low a third time, playback of the current message starts again from

its beginning. If you hold the /M1_MESSAGE pin low continuously the same message will play

continuously in a looping fashion. A 1,540ms period of silence is inserted during looping as an

indicator to the user of the transition between the beginning and end of the message. Note that in

auto rewind mode the device always rewinds to the beginning of the current message. To listen

to a subsequent message the device must be fast forwarded past the current message to the next

message. This function is accomplished by toggling the /M2_NEXT pin from high to low. The

pulse must be low for least 400 cycles of the sampling clock. After the device is incremented to

the desired message the user can initiate playback of the message with the playback sequence

described above. A special case exists when the /M2_NEXT pin goes low during playback.

Playback of the current message will stop, the device will beep, advance to the next message and

initiate playback of the next message. (Note that if /M2 Next goes low when not in playback

mode, the device will prepare to play the next message, but will not actually initiate playback). If

the /CE pin goes high during playback, playback of the current message will stop, the device will

beep, reset to the beginning of the first message, and wait for a subsequent playback command.

When you reach the end of the memory array, any subsequent pulsing of /M1_MESSAGE or

/M2_NEXT will only result in a double beep. To proceed from this state the user must rewind

the device to the beginning of the memory array. This can be accomplished by toggling the /CE

pin low or cycling power.

3.1.3.2A Functional Description of Recording In Tape Mode using the Normal Option

On power-up, the device is ready to record or playback, starting at the first address in the

memory array. Before you can begin recording, the /CE input must be set to low to enable the

device and /RE must be set to low to enable recording. On a falling edge of the /M1_MESSAGE

pin the device will beep once and initiate recording. A subsequent rising edge on the /M1

Message pin will stop recording and insert a single beep. If the M1_MESSAGE pin is held low

beyond the end of the available memory, recording Stops automatically, and two beeps are

inserted; regardless of the state of the /M1_MESSAGE pin. The device returns to the standby

mode when the /M1_MESSAGE pin is returned high. A subsequent falling edge on the

/M1_MESSAGE pin starts a new record operation in the memory array immediately following

the last recorded message, thus preserving the last recorded message. To record over all previous

messages you must pulse the /CE pin low once to reset the device to the beginning of the first

message. You can then initiate a record sequence, as described above, to record a new message.

The most recently recorded message will become the last recorded message and all previously

recorded messages following this message will become inaccessible. If you wish to preserve any

current messages it is recommend that the Auto Rewind option be used instead of the Normal

option. If the Normal option is necessary the following sequence can be used. To preserve

current messages you must fast forward past the messages you want to keep before you can

record a new message. To fast forward when using the Normal option you must switch to play

mode and listen to messages sequentially until you arrive at the beginning of the message you

wish to overwrite. At this stage you should switch back to record mode and overwrite the desired

message.

The most recently recorded message will become the last recorded message and all previously

recorded messages following this message will become inaccessible. All inputs, except /CE, are

ignored during recording.

3.1.3.2B Functional Description of Playback in Tape Mode using the Normal Option

On power-up or after a low to high transition on /RE the device is ready to record or playback

starting at the first address in the memory array. Before you can begin playback of messages,

the /CE input must be set to low to enable the device and /RE must be set to high to enable

playback. The first high to low going pulse of the /M1_MESSAGE pin initiates playback from

the beginning of the current message. When the /M1_MESSAGE pin pulses from high to low a

second time, playback of the current message stops immediately. When the /M1_MESSAGE pin

pulses from high to low a third time, playback of the next message starts again from the

beginning. If you hold the /M1_MESSAGE pin low continuously, the current message and

subsequent messages play until the one of the following conditions is met: the end of the

memory array is reached, the last message is reached, the /M1_message pin is released. If the last

recorded message has already played, any further transitions on the /M1_MESSAGE pin will

initiate a double beep for warning and the /M7_END pin will go low. To exit this state you must

pulse the /CE pin high and then low once during standby to reset the pointer to the beginning of

the first message.

3.2 Microprocessor Controlled Message Management:

The APR9600 device incorporates several features design help simplify microprocessor

Controlled message management When controlling messages the microprocessor essentially

toggles pins as described in the message management sections described previously. The /BUSY,

/STROBE, and /M7_END pins are included to simplify handshaking between the microprocessor

and the APR9600. The /BUSY pin, when low, indicates to the host processor that the device is

busy and that No commands can be accepted. When this pin is high the device is ready to accept

and execute commands from the host. The /STROBE pin pulses low each time a memory

segment is used. Counting pulses on this pin enables the host processor to accurately determine

how much recording time has been used, and how much recording time remains. The APR9600

has a total of eighty memory segments. The /M7_END pin is used as an indicator that the device

has stopped its current record or playback operation.

During recording a low going pulse indicates that all memory has been used. During playback a

low pulse indicates that the last message has played. Microprocessor control can also be used to

link several APR9600 devices together in order to increase total available recording time. In this

application both the speaker and microphone signals can be connected in parallel. The

microprocessor will then control which device currently drives the speaker by enabling or

disabling each device using its respective /CE pins. A continuous message cannot be recorded in

multiple devices however because the transition from one device to the next will incur a delay

that is noticeable upon playback. For this reason it is recommended that message boundaries and

device boundaries always coincide.

3.3 Signal Storage:

The APR9600 samples incoming voice signals and stores the instantaneous voltage samples in

non-volatile FLASH memory cells. Each memory cell can support voltage ranges from 0 to 256

levels. These 256 discrete voltage levels are the equivalent of 8-bit (28=256) binary encoded

values. During playback the stored signals are retrieved from memory, smoothed to form a

continuous signal, and then amplified before being fed to an external speaker.

3.4 Sampling Rate & Voice Quality:

According to Shannon's sampling theorem, the highest possible frequency component introduced

to the input of a sampling system must be equal to or less than half the sampling frequency if

aliasing errors are to be eliminated. The APR9600 automatically filters its input, based on the

selected sampling frequency, to meet this requirement. Higher sampling rates increase the

bandwidth and hence the voice quality, but they also use more memory cells for the same length

of recording time. Lower sampling rates use fewer memory cells and effectively increase the

duration capabilities of the device, but they also reduce incoming signal bandwidth. The

APR9600 accommodates sampling rates as high as 8 kHz and as low a 4 kHz. You can control

the quality/duration trade off by controlling the sampling frequency.

An internal oscillator provides the APR9600 sampling clock. Changing the resistance

from the OscR pin to GND. Table2 summarizes resistance values and the corresponding

sampling frequencies, as can change oscillator frequency well as the resulting input bandwidth

and duration.

3.5 Automatic Gain Control (AGC):

The APR9600 device has an integrated AGC. The AGC affects the microphone input but

does not affect the ANA_IN input. The AGC circuit insures that the input signal is properly

amplified. The AGC works by applying maximum gain to small input signals and minimum gain

to large input signals. This assures that inputs of varying amplitude are recorded at the optimum

signal level. The AGC amplifier is designed to have a fast attack time and a slow decay time.

This timing is controlled by the RC network connected to pin 19. A value of 220K and 4.7uF has

been found to work well for the English language. Be aware that different languages, speakers

from different countries, and music may all require modification of the recommended values for

the AGC RC network.

3.6 Sampling Application:

The following reference schematics are included as examples of how a recording system

might be designed. Each reference schematic shows the device incorporated in one of its three

main modes: Random Access, Tape mode – Normal option, and Tape mode – Auto Rewind

option. Note that in several of the applications either one or all of the /BUSY, /STROBE, or

/M7_END pins are connected to LEDs as indicators of device status. This is possible because all

of these pins and signals were designed to have timing compatible with both microprocessor

interface and manual LED indication. A bias must be applied to the electrets microphone in order

to power its built-in circuitry. The ground return of this bias network is connected to the /Busy.

This configuration saves power when record mode. Both pins 18 and 19, MicIn and

MicRef, must be AC coupled to the microphone network in order to block the DC biasing

voltage. Figure 3 shows the device configured in random access mode. The device is using eight

Message segments, the maximum available, in this mode. Note that message trigger pins that are

not used, for modes with less than eight segments, can be left unconnected with the exception of

pin /M8_OPTION which should be pulled to VCC through a 100k resistor.

Fig 14: Random Access Mode

Fig 15: Tape Mode, Auto Rewind option

Fig 16: Tape Mode, Normal option

Liquid crystal display

Liquid crystal displays (LCDs) have materials, which combine the properties of both liquids and crystals. Rather than having a melting point, they have a temperature

range within which the molecules are almost as mobile as they would be in a liquid, but are grouped together in an ordered form similar to a crystal.

An LCD consists of two glass panels, with the liquid crystal material sand witched in

between them. The inner surface of the glass plates are coated with transparent electrodes which

define the character, symbols or patterns to be displayed polymeric layers are present in between

the electrodes and the liquid crystal, which makes the liquid crystal molecules to maintain a

defined orientation angle.

One each polarisers are pasted outside the two glass panels. These polarisers would rotate

the light rays passing through them to a definite angle, in a particular direction.

When the LCD is in the off state, light rays are rotated by the two polarisers and the

liquid crystal, such that the light rays come out of the LCD without any orientation, and hence

the LCD appears transparent.

When sufficient voltage is applied to the electrodes, the liquid crystal molecules would be

aligned in a specific direction. The light rays passing through the LCD would be rotated by the

polarisers, which would result in activating/ highlighting the desired characters.

The LCD’s are lightweight with only a few millimeters thickness. Since the LCD’s

consume less power, they are compatible with low power electronic circuits, and can be powered

for long durations.

The LCD’s don’t generate light and so light is needed to read the display. By using

backlighting, reading is possible in the dark. The LCD’s have long life and a wide operating

temperature range.

Changing the display size or the layout size is relatively simple which makes the LCD’s

more customers friendly.

The LCDs used exclusively in watches, calculators and measuring instruments are the

simple seven-segment displays, having a limited amount of numeric data. The recent advances in

technology have resulted in better legibility, more information displaying capability and a wider

temperature range. These have resulted in the LCDs being extensively used in

telecommunications and entertainment electronics. The LCDs have even started replacing the

cathode ray tubes (CRTs) used for the display of text and graphics, and also in small TV

applications.

This section describes the operation modes of LCD’s then describe how to program and

interface an LCD to 8051 using Assembly and C.

LCD operationIn recent years the LCD is finding widespread use replacing LEDs(seven-segment LEDs

or other multisegment LEDs).This is due to the following reasons:

1. The declining prices of LCDs.

2. The ability to display numbers, characters and graphics. This is in

contract to LEDs, which are limited to numbers and a few characters.

3. Incorporation of a refreshing controller into the LCD, there by

relieving the CPU of the task of refreshing the LCD. In the contrast,

the LED must be refreshed by the CPU to keep displaying the data.

4. Ease of programming for characters and graphics.

LCD pin description The LCD discussed in this section has 14 pins. The function of each pins is given in

table.

TABLE 1:Pin description for LCD:

Pin symbol I/O Description

1 Vss -- Ground

2 Vcc -- +5V power supply

3 VEE -- Power supply to

control contrast

4 RS I RS=0 to select

command register

RS=1 to select

data register

5 R/W I R/W=0 for write

R/W=1 for read

6 E I/O Enable

7 DB0 I/O The 8-bit data bus

8 DB1 I/O The 8-bit data bus

9 DB2 I/O The 8-bit data bus

10 DB3 I/O The 8-bit data bus

11 DB4 I/O The 8-bit data bus

12 DB5 I/O The 8-bit data bus

13 DB6 I/O The 8-bit data bus

14 DB7 I/O The 8-bit data bus

TABLE 2: LCD Command Codes

Code

(hex)

Command to LCD Instruction

Register

1 Clear display screen

2 Return home

4 Decrement cursor

6 Increment cursor

5 Shift display right

7 Shift display left

8 Display off, cursor off

A Display off, cursor on

C Display on, cursor off

E Display on, cursor on

F Display on, cursor blinking

10 Shift cursor position to left

14 Shift cursor position to right

18 Shift the entire display to the left

1C Shift the entire display to the right

80 Force cursor to beginning of 1st line

C0 Force cursor to beginning of 2nd line

38 2 lines and 5x7 matrix

Uses:

The LCDs used exclusively in watches, calculators and measuring instruments

are the simple seven-segment displays, having a limited amount of numeric data. The recent

advances in technology have resulted in better legibility, more information displaying capability

and a wider temperature range. These have resulted in the LCDs being extensively used in

telecommunications and entertainment electronics. The LCDs have even started replacing the

cathode ray tubes (CRTs) used for the display of text and graphics, and also in small TV

applications.

LCD INTERFACING

Sending commands and data to LCDs with a time delay:

Fig 21: Interfacing of LCD to a micro controller

To send any command from table 2 to the LCD, make pin RS=0.

for data, make RS=1.Then send a high –to-low pulse to the E pin to enable the internal latch of the LCD.

Power supply

The power supplies are designed to convert high voltage AC mains

electricity to a suitable low voltage supply for electronics circuits and other devices. A power

supply can by broken down into a series of blocks, each of which performs a particular function.

A d.c power supply which maintains the output voltage constant irrespective of a.c mains

fluctuations or load variations is known as “Regulated D.C Power Supply”

For example a 5V regulated power supply system as shown below:

Transformer:

A transformer is an electrical device which is used to convert electrical power from one Electrical circuit to another without change in frequency.

Transformers convert AC electricity from one voltage to another with little loss of power. Transformers work only with AC and this is one of the reasons why mains

electricity is AC. Step-up transformers increase in output voltage, step-down transformers decrease in output voltage. Most power supplies use a step-down transformer to reduce the dangerously high mains voltage to a safer low voltage. The input coil is called the primary

and the output coil is called the secondary. There is no electrical connection between the two coils; instead they are linked by an alternating magnetic field created in the soft-iron core of the transformer. The two lines in the middle of the circuit symbol represent the

core. Transformers waste very little power so the power out is (almost) equal to the power in. Note that as voltage is stepped down current is stepped up. The ratio of the number of turns on each coil, called the turn’s ratio, determines the ratio of the voltages. A step-down transformer has a large number of turns on its primary (input) coil which is connected to the high voltage mains supply, and a small number of turns on its secondary (output) coil

to give a low output voltage.

An Electrical Transformer

Turns ratio = Vp/ VS = Np/NS

Power Out= Power In

VS X IS=VP X IP

Vp = primary (input) voltage

Np = number of turns on primary coil

Ip  = primary (input) current    

RECTIFIER:

A circuit which is used to convert a.c to dc is known as RECTIFIER. The process of conversion a.c to d.c is called “rectification”

TYPES OF RECTIFIERS: Half wave Rectifier Full wave rectifier

1. Centre tap full wave rectifier.2. Bridge type full bridge rectifier.

Comparison of rectifier circuits:

Parameter Type of Rectifier

Half wave Full wave BridgeNumber of diodes

1 2

4

PIV of diodes Vm

2Vm

Vm

D.C output voltage Vm/

2Vm/

2Vm/

Vdc,at no-load

0.318Vm

0.636Vm 0.636Vm

Ripple factor 1.21

0.482

0.482

Ripple frequency

f

2f

2f

Rectification efficiency

0.406

0.812

0.812

Transformer Utilization Factor(TUF)

0.287 0.693 0.812

RMS voltage Vrms Vm/2 Vm/√2 Vm/√2

Full-wave Rectifier:

From the above comparision we came to know that full wave bridge rectifier as more advantages than the other two rectifiers. So, in our project we are using full wave bridge rectifier circuit.

Bridge Rectifier: A bridge rectifier makes use of four diodes in a bridge arrangement to achieve

full-wave rectification. This is a widely used configuration, both with individual diodes wired as

shown and with single component bridges where the diode bridge is wired internally.

A bridge rectifier makes use of four diodes in a bridge arrangement as shown in fig(a) to

achieve full-wave rectification. This is a widely used configuration, both with individual diodes

wired as shown and with single component bridges where the diode bridge is wired internally.

Fig(A)

Operation:

During positive half cycle of secondary, the diodes D2 and D3 are in forward biased while D1

and D4 are in reverse biased as shown in the fig(b). The current flow direction is shown in the

fig (b) with dotted arrows.

Fig(B)During negative half cycle of secondary voltage, the diodes D1 and D4 are in forward biased

while D2 and D3 are in reverse biased as shown in the fig(c). The current flow direction is

shown in the fig (c) with dotted arrows.

Fig(C)

Filter: A Filter is a device which removes the a.c component of rectifier output

but allows the d.c component to reach the load

Capacitor Filter:

We have seen that the ripple content in the rectified output of half wave rectifier is 121% or

that of full-wave or bridge rectifier or bridge rectifier is 48% such high percentages of ripples is

not acceptable for most of the applications. Ripples can be removed by one of the following

methods of filtering.

(a) A capacitor, in parallel to the load, provides an easier by –pass for the ripples voltage though

it due to low impedance. At ripple frequency and leave the d.c.to appears the load.

(b) An inductor, in series with the load, prevents the passage of the ripple current (due to high

impedance at ripple frequency) while allowing the d.c (due to low resistance to d.c)

(c) various combinations of capacitor and inductor, such as L-section filter section filter,

multiple section filter etc. which make use of both the properties mentioned in (a) and (b) above.

Two cases of capacitor filter, one applied on half wave rectifier and another with full wave

rectifier.

Filtering is performed by a large value electrolytic capacitor connected across the DC supply to act as a reservoir, supplying current to the output when the varying DC voltage from the rectifier is falling. The capacitor charges quickly near the peak of the

varying DC, and then discharges as it supplies current to the output. Filtering significantly increases the average DC voltage to almost the peak value (1.4 × RMS value).

To calculate the value of capacitor(C), C = ¼*√3*f*r*Rl

Where, f = supply frequency,

r = ripple factor, Rl = load resistance

Note: In our circuit we are using 1000µF Hence large value of capacitor is placed to reduce ripples and to improve the DC component.

Regulator: Voltage regulator ICs is available with fixed (typically 5, 12 and 15V) or variable output

voltages. The maximum current they can pass also rates them. Negative voltage regulators are

available, mainly for use in dual supplies. Most regulators include some automatic protection

from excessive current ('overload protection') and overheating ('thermal protection'). Many of

the fixed voltage regulator ICs have 3 leads and look like power transistors, such as the 7805

+5V 1A regulator shown on the right. The LM7805 is simple to use. You simply connect the

positive lead of your unregulated DC power supply (anything from 9VDC to 24VDC) to the

Input pin, connect the negative lead to the Common pin and then when you turn on the power,

you get a 5 volt supply from the output pin.

Fig 6.1.6 A Three Terminal Voltage Regulator

78XX:

The Bay Linear LM78XX is integrated linear positive regulator with three terminals. The

LM78XX offer several fixed output voltages making them useful in wide range of applications.

When used as a zener diode/resistor combination replacement, the LM78XX usually results in an

effective output impedance improvement of two orders of magnitude, lower quiescent current.

The LM78XX is available in the TO-252, TO-220 & TO-263packages,

Features:

• Output Current of 1.5A

• Output Voltage Tolerance of 5%

• Internal thermal overload protection

• Internal Short-Circuit Limited

• No External Component

• Output Voltage 5.0V, 6V, 8V, 9V, 10V,12V, 15V, 18V, 24V

• Offer in plastic TO-252, TO-220 & TO-263

• Direct Replacement for LM78XX

MOTOR DRIVER

L293D:

The L293 is an integrated circuit motor driver that can be used for simultaneous, bi-directional

control of two small motors. Small means small. The L293 is limited to 600 mA, but in reality

can only handle much small currents unless you have done some serious heat sinking to keep the

case temperature down. Unsure about whether the L293 will work with your motor? Hook up the

circuit and run your motor while keeping your finger on the chip. If it gets too hot to touch, you

can't use it with your motor. (Note to ME2011 students: The L293 should be OK for your small

motor but is not OK for your gear motor.)

The L293 comes in a standard 16-pin, dual-in line integrated circuit package. There is an L293

and an L293D part number. Pick the "D" version because it has built in flyback diodes to

minimize inductive voltage spikes.

The pinout for the L293 in the 16-pin package is shown below in top view. Pin 1 is at the top left

when the notch in the package faces up. Note that the names for pin functions may be slightly

different than what is shown in the following diagrams.

The following schematic shows how to connect the L293 to your motor and the Stamp. Each

motor takes 3 Stamp pins. If you are only using one motor, leave pins 9, 10, 11, 12, 13, 14, and

15 empty.

Assume you have only one motor connected with the enable tied to Stamp Pin 0, and the two

direction controls tied to Stamp Pins 1 and 2.

Here is a table describing the control pin functions.

ENABLE DIRA DIRB Function

H H L Turn right

H L H Turn left

H L/H L/H Fast stop

L either either Slow stop

 And here is a short sample program that exercises the L293.

advantage: 

You can control 2 motors in both directions instead of 4 in only one direction. 

Disadvantages: 

There is a 1.5V voltage drop within the L293D driver chip.

If you run both motors and servos on the same circuit, your servos will always get 1.5V more than the motors - and typically you would want it the other way around! 

DC GEARED MOTOR 12V 60RPM:(robotics)

60RPM 12V DC geared motors for robotics applications. Very easy to use and available in

standard size. Nut and threads on shaft to easily connect and internal threaded shaft for easily

connecting it to wheel. 

Features: 60RPM 12V DC motors with Gearbox

3000RPM base motor

6mm shaft diameter with internal hole

125gm weight

Same size motor available in various rpm

2kgcm torque

No-load current = 60 mA(Max), Load current = 300 mA(Max)

Circuit description:

In this project we required operating voltage for Microcontroller 89S52 is 5V. Hence the 5V

D.C. power supply is needed for the IC’s. This regulated 5V is generated by stepping down the

voltage from 230V to 18V now the step downed a.c voltage is being rectified by the Bridge

Rectifier using 1N4007 diodes. The rectified a.c voltage is now filtered using a ‘C’ filter. Now

the rectified, filtered D.C. voltage is fed to the Voltage Regulator. This voltage regulator

provides/allows us to have a Regulated constant Voltage which is of +5V. The rectified; filtered

and regulated voltage is again filtered for ripples using an electrolytic capacitor 100μF. Now the

output from this section is fed to 40th pin of 89S52 microcontroller to supply operating voltage.

The microcontroller 89S52 with Pull up resistors at Port0 and crystal oscillator of 11.0592 MHz

crystal in conjunction with couple of 30-33pf capacitors is placed at 18th & 19th pins of 89S52 to

make it work (execute) properly. In this project Depending on the direction of the MEMS,

Directions of the vehicle may be LEFT, RIGHT, FRONT, and BACK as per the commands

given by MEMS. The microcontroller will change the direction of the vehicle and also gives the

voice announcement using the voice IC and loud speaker.

SOFTWARE DESCRIPTION

ABOUT SOFTWARE

Software used:*Keil software for c programming

ABOUT KEIL SOFTWARE:

It is possible to create the source files in a text editor such as Notepad, run the Compiler on each C source file, specifying a list of controls, run the Assembler on each Assembler source file, specifying another list of controls, run either the Library Manager or Linker (again specifying a list of controls) and finally running the Object-HEX Converter to convert the Linker output file to an Intel Hex File. Once that has been completed the Hex File can be downloaded to the target hardware and debugged. Alternatively KEIL can be used to create source files; automatically compile, link and covert using options set with an easy to use user interface and finally simulate or perform debugging on the hardware with access to C variables and memory. Unless you have to use the tolls on the command line, the choice is clear. KEIL Greatly simplifies the process of creating and testing an embedded application.

Projects:

The user of KEIL centers on “projects”. A project is a list of all the source files required to build a single application, all the tool options which specify exactly how to build the application, and – if required – how the application should be simulated. A project contains enough information to take a set of source files and generate exactly the binary code required for the application. Because of the high degree of flexibility required from the tools, there are many options that can be set to configure the tools to operate in a specific manner. It would be tedious to have to set these options up every time the application is being built; therefore they are stored in a project file. Loading the project file into KEIL informs KEIL which source files are required, where they are, and how to configure the tools in the correct way. KEIL can then execute each tool with the correct options. It is also possible to create new projects in KEIL. Source files are added to the project and the tool options are set as required. The project can then be saved to preserve the settings. The project is reloaded and the simulator or debugger started, all the desired windows are opened. KEIL project files have the extension Simulator/Debugger:

The simulator/ debugger in KEIL can perform a very detailed simulation of a micro controller along with external signals. It is possible to view the precise execution time of a single assembly instruction, or a single line of C code, all the way up to the entire application, simply by entering the crystal frequency. A window can be opened for each peripheral on the device, showing the state of the peripheral. This enables quick trouble shooting of mis-configured peripherals. Breakpoints may be set on either assembly instructions or lines of C code, and execution may be stepped through one instruction or C line at a time. The contents of all the

memory areas may be viewed along with ability to find specific variables. In addition the registers may be viewed allowing a detailed view of what the microcontroller is doing at any point in time. The Keil Software 8051 development tools listed below are the programs you use to compile your C code, assemble your assembler source files, link your program together, create HEX files, and debug your target program. µVision2 for Windows™ Integrated Development Environment: combines Project Management, Source Code Editing, and Program Debugging in one powerful environment. C51 ANSI Optimizing C Cross Compiler: creates relocatable object modules from your C

source code, A51 Macro Assembler: creates relocatable object modules from your 8051

assembler source code, BL51 Linker/Locator: combines relocatable object modules created by the compiler and

assembler into the final absolute object module, LIB51 Library Manager: combines object modules into a library, which may be used by the

linker, OH51 Object-HEX Converter: creates Intel HEX files from absolute object modules.

What's New in µVision3?

µVision3 adds many new features to the Editor like Text Templates, Quick Function Navigation, and Syntax Coloring with brace high lighting Configuration Wizard for dialog based startup and debugger setup. µVision3 is fully compatible to µVision2 and can be used in parallel with µVision2.

What is µVision3?

µVision3 is an IDE (Integrated Development Environment) that helps you write, compile, and debug embedded programs. It encapsulates the following components:

A project manager. A make facility. Tool configuration. Editor. A powerful debugger.

To help you get started, several example programs (located in the \C52\Examples, \C251\Examples, \C166\Examples, and \ARM\...\Examples) are provided.

HELLO is a simple program that prints the string "Hello World" using the Serial Interface.

MEASURE is a data acquisition system for analog and digital systems. TRAFFIC is a traffic light controller with the RTX Tiny operating system. SIEVE is the SIEVE Benchmark. DHRY is the Dhrystone Benchmark. WHETS is the Single-Precision Whetstone Benchmark.

Additional example programs not listed here are provided for each device architecture.

Building an Application in µVision2

To build (compile, assemble, and link) an application in µVision2, you must:1. Select Project -(forexample,166\EXAMPLES\HELLO\HELLO.UV2).2. Select Project - Rebuild all target files or Build target.

µVision2 compiles, assembles, and links the files in your project

Creating Your Own Application in µVision2

To create a new project in µVision2, you must:1. Select Project - New Project.2. Select a directory and enter the name of the project file.3. Select Project - Select Device and select an 8052, 251, or C16x/ST10 device from the

Device Database™.4. Create source files to add to the project.5. Select Project - Targets, Groups, Files. Add/Files, select Source Group1, and add the

source files to the project.6. Select Project - Options and set the tool options. Note when you select the target device

from the Device Database™ all special options are set automatically. You typically only need to configure the memory map of your target hardware. Default memory model settings are optimal for most applications.

7. Select Project - Rebuild all target files or Build target.

Debugging an Application in µVision2

To debug an application created using µVision2, you must:1. Select Debug - Start/Stop Debug Session.2. Use the Step toolbar buttons to single-step through your program. You may enter G,

main in the Output Window to execute to the main C function.3. Open the Serial Window using the Serial #1 button on the toolbar.

Debug your program using standard options like Step, Go, Break, and so on.Starting µVision2 and Creating a ProjectµVision2 is a standard Windows application and started by clicking on the program icon. To create a new project file select from the µVision2 menuProject – New Project…. This opens a standard Windows dialog that asks youfor the new project file name.We suggest that you use a separate folder for each project. You can simply usethe icon Create New Folder in this dialog to get a new empty folder. Thenselect this folder and enter the file name for the new project, i.e. Project1.µVision2 creates a new project file with the name PROJECT1.UV2 which containsa default target and file group name. You can see these names in the ProjectWindow – Files.Now use from the menu Project – Select Device for Target and select a CPUfor your project. The Select Device dialog box shows the µVision2 devicedatabase. Just select the micro controller you use. We are using for our examples the Philips 89S52RD+ CPU. This selection sets necessary tooloptions for the 89S52RD+ device and simplifies in this way the tool Configuration Building Projects and Creating a HEX FilesTypical, the tool settings under Options – Target are all you need to start a newapplication. You may translate all source files and line the application with aclick on the Build Target toolbar icon. When you build an application withsyntax errors, µVision2 will display errors and warning messages in the OutputWindow – Build page. A double click on a message line opens the source fileon the correct location in a µVision2 editor window.

Once you have successfully generated your application you can start debugging.

After you have tested your application, it is required to create an Intel HEX file to download the software into an EPROM programmer or simulator. µVision2 creates HEX files with each build process when Create HEX files under Options for Target – Output is enabled. You may start your PROM programming utility after the make process when you specify the program under the option Run User Program #1.CPU Simulation:µVision2 simulates up to 16 Mbytes of memory from which areas can beMapped for read, write, or code execution access. The µVision2 simulator trapsAnd reports illegal memory accesses.In addition to memory mapping, the simulator also provides support for theIntegrated peripherals of the various 89S52 derivatives. The on-chip peripheralsof the CPU you have selected are configured from the Device.Database selection:you have made when you create your project target. Refer to page 58 for moreInformation about selecting a device. You may select and display the on-chip peripheral components using the Debug menu. You can also change the aspects of each peripheral using the controls in the dialog boxes.Start Debugging:You start the debug mode of µVision2 with the Debug – Start/Stop DebugSession command. Depending on the Options for Target – DebugConfiguration, µVision2 will load the application program and run the startupcode µVision2 saves the editor screen layout and restores the screen layout of the last debug session. If the program execution stops, µVision2 opens aneditor window with the source text or shows CPU instructions in the disassembly window. The next executable statement is marked with a yellow arrow. During debugging, most editor features are still available. For example, you can use the find command or correct program errors. Program source text of your application is shown in the same windows. The µVision2 debug mode differs from the edit mode in the following aspects:_ The “Debug Menu and Debug Commands” described on page 28 areAvailable. The additional debug windows are discussed in the following._ The project structure or tool parameters cannot be modified. All buildCommands are disabled.

Disassembly WindowThe Disassembly window shows your target program as mixed source and assembly program or just assembly code. A trace history of previously executed instructions may be displayed with Debug – View Trace Records. To enable the trace history, set Debug – Enable/Disable Trace Recording. If you select the Disassembly Window as the active window all program step commands work on CPU instruction level rather than program source lines. You can select a text line and set or modify code breakpoints using toolbar buttons or the context menu commands.

You may use the dialog Debug – Inline Assembly… to modify the CPU instructions. That allows you to correct mistakes or to make temporary changes to the target program you are debugging.

SOFTWARE COMPONENTS

About Keil

1. Click on the Keil u Vision Icon on Desktop

2. The following fig will appear

3. Click on the Project menu from the title bar

4. Then Click on New Project

5. Save the Project by typing suitable project name with no extension in u r own folder sited in either C:\ or D:\

6. Then Click on Save button above.

7. Select the component for u r project. i.e. Atmel……

8. Click on the + Symbol beside of Atmel

9. Select AT89S52 as shown below

10. Then Click on “OK”

11. The Following fig will appear

12. Then Click either YES or NO………mostly “NO”

13. Now your project is ready to USE

14. Now double click on the Target1, you would get another option “Source group 1” as

shown in next page.

15. Click on the file option from menu bar and select “new”

16. The next screen will be as shown in next page, and just maximize it by double

clicking on its blue boarder.

17. Now start writing program in either in “C” or “ASM”

18. For a program written in Assembly, then save it with extension “. asm” and for “C”

based program save it with extension “ .C”

19. Now right click on Source group 1 and click on “Add files to Group Source”

20. Now you will get another window, on which by default “C” files will appear.

21. Now select as per your file extension given while saving the file

22. Click only one time on option “ADD”

23. Now Press function key F7 to compile. Any error will appear if so happen.

24. If the file contains no error, then press Control+F5 simultaneously.

25. The new window is as follows

26. Then Click “OK”

27. Now Click on the Peripherals from menu bar, and check your required port as shown

in fig below

28. Drag the port a side and click in the program file.

29. Now keep Pressing function key “F11” slowly and observe.

30. You are running your program successfully

Conclusion

The project “GESTURE BASED VEHICLE MOVEMENTS CONTROL AND

ALERTING SYSTEM” has been successfully designed and tested.

Integrating features of all the hardware components used have developed it. Presence of

every module has been reasoned out and placed carefully thus contributing to the best working of

the unit.

Secondly, using highly advanced IC’s and with the help of growing technology the

project has been successfully implemented.

BIBLIOGRAPHY

The 8051 Micro controller and Embedded Systems

-Muhammad Ali Mazidi

Janice Gillispie Mazidi

The 8051 Micro controller Architecture, Programming & Applications

-Kenneth J. Ayala

Fundamentals Of Micro processors and Micro computers

-B. Ram

Micro processor Architecture, Programming & Applications

- Ramesh S. Gaonkar

Electronic Components

-D.V. Prasad

Wireless Communications

- Theodore S. Rappaport

Mobile Tele Communications

- William C.Y. Lee