Robotcup Guide Book

8/4/2019 Robotcup Guide Book

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8051 Basic Connection

fig1: 8051 basic connection

Push Button (tact switch) with LED indicator

fig2: push button (tact switch) with LED indicator

When button is LED Logic State

Pushed Light On 0

Not Pushed Light Off 1


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+5V DC Voltage Supply

fig3: voltage regulator connection

Component Description

1N4001 This rectifier diodes function is to protect voltage regulator 7805 from

being damaged by reverse polarity battery input. Its forward bias voltage

is around 1.1V thus the effective voltage supply to 7805 is +10.9V (12V

1.1V = 10.9V)C1, C4 They smooth the voltage level.

C2, C3 They are used to suppress high frequency noise. The impedance of

capacitor is Xc = 1/j2fc, where f is frequency and c is capacitance.The higher the frequency, the lower the impedance. Effectively, high

frequency noise is being filtered.

7805 Normal 7805 can supply 1.0A current. For proper operation, the inputvoltage should at least +9V.

Relay configuration of H-Bridge

*bat = batteryfig4: H-bridge connection


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Component Description

74HC04 It is a Hex Inverter to act as a

buffer between microcontroller and

the ULN2803.It inverts the input logic at the

output side.

Input Output

nA nY

L (Logic 0) H (Logic 1)

H (Logic 1) L (Logic 0)

*H = HIGH voltage levelL = LOW voltage level

ULN2803 This is Darlington Transistor

Arrays used to drive high current

load such as dc motor.

C1 It is used for high frequency noise filtering.R1, R2 To limit the current flows through the LED. A normal LED (3mm)

requires 10mA to emit light.V = IR thus R = V / I = 12V / 10mA = 1.2K

H-Bridge It mainly consists of 2 12V relay, namely RLY1 and RLY2.

P0.0 D1 P0.1 D2 Motor state

L On L On Stop

L On H Off CCW

H Off L On CW

H Off H Off Stop

*H = HIGH voltage levelL = LOW voltage level

CW = Clockwise direction (assume that current flow from M1 to M2

is CW)CCW = Counter Clockwise direction (assume that current flow from

M2 to M1 is CCW)


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Extra Note on H-Bridge

fig5: Comparison of pin layout of real relay component and the schematic symbol

fig6: Basic H-Bridge.


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H-Bridge Working Principle

fig7: Clock-Wise (CW) direction

NO = Normally Open

NC = Normally CloseCOM = Common

Coil1 = one side of coil named as coil1Coil2 = another side of coil named as coil2

Clock-Wise (CW) direction

1. When P0.1 is cleared (LOW state), 74HC04 will invert it and output to 2Y as

HIGH state. This High state will be inverted again by ULN2803 to LOWstate at pin 17.

2. Since there is a voltage difference between Coil1 and Coil2 (relay on your right

hand side), current will flows through the coil and generate magnetic field to pullthe internal switch from NC to NO.

3. Now a voltage difference appears between M1 and M2. Thus current flows from

+12V terminal -> M1 -> M2 -> GND. (assume that current flow from M1 to M2is CW)


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fig8: Counter Clock-Wise (CCW) direction

Counter Clock-Wise (CCW) direction

4. When P0.0 is cleared (LOW state), 74HC04 will invert it and output to 1Y as

HIGH state. This High state will be inverted again by ULN2803 to LOWstate at pin 18.

5. Since there is a voltage difference between Coil1 and Coil2 (relay on your right

hand side), current will flows through the coil and generate magnetic field to pull

the internal switch from NC to NO.6. Now a voltage difference appears between M1 and M2. Thus current flows from

+12V terminal -> M2 -> M1 -> GND. (assume that current flow from M2 to M1

is CCW)


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Programming

Below are the simple assembly codes that can perform triggering the relay by pressing abutton.;Simple button pressing and trigger on relays assembly code.

ORG 0000

MAIN: SETB P2.0 ;clear P2.0, and wait for another button pressSETB P2.1 ;clear P2.1, and wait for another button press

OK1: JNB P1.0, RELAY1 ;wait for P1.0 button press, and jump to Relay1JNB P1.1, RELAY2 ;wait for P1.0 button press, and jump to Relay1JMP MAIN

RELAY1: CLR P2.0 ;trigger on relay at P2.0JMP OK1 ;jump back button press inspection loop

RELAY2: CLR P2.1 ;trigger on relay at P2.1JMP OK1 ;jump back button press inspection loop

END

Description of the code:Button1 = Pin 1.0 of the micro-controller

Button2= Pin 1.1 of the micro-controllerRelay1= Pin 2.0 require to connect to a transistor to trigger on the first relay.

Relay2= Pin 2.1 require to connect to a transistor to trigger on the second relay.

Operation of the code:

The operation of this code is simple.

When you press the button1 (that require to grounding the P1.0), relay1 will turn on (with

pin2.0 set to low that will turn on a PNP transistor for trigger on a relay).When yourelease pressing button1, P2.0 will set to high, and relay1 will turn off.

The same response will show with respective pin configuration when youpressing/release button2.

Step by step of using Fet89c5x.

Step1


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- Write your code in Fet89c5x.

Step2

-go to -> file, -> save as; to save your code that you had wrote to a specific location.


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Step3

- Compile your code by pressing the build icon .- A .hex file will generate after compile the code.

- There will be a massage box to show how many errors in your code.

Step by step of using 8052Simulator.


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Step1

- Open 8052SIM.exe (this program not requires to install).

- Go to View, and then select I/O ports and SFR window.- I/O ports window is for you to observe the I/O ports response; SFR window is for you

to observe Special Function Registers value while program running.

Step2

-open the .hex file from respective location that you had save your code.


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Step3

- Run your program (by pressing the icon ) and observe the Ports window

response.

- Un-tick (set low) the P1.0 box at the Ports window. You will see P2.0 box also

follow un-tick. Tick (set high) the P1.0 box, P2.0 will follow to tick back.

- The same response will show when you tick/ un-tick P1.1 box.


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Following are the sample code for simple LED blinking.;simple led blinking

ORG 0000HMOV P1, 0FFHMOV P2, 0FFH

START: JNB P1.0 , LEDBLINK JMP START

STOP: CLR P2.0JMP START

LEDBLINK: CLR P2.0CALL DELAY_1SECCLR P2.0JNB P1.1, STOPJMP LEDBLINK

;The subroutine below causes a delay of 1 second;(crystal frequency = 12 MHz)

DELAY_1SEC:MOV R0, #4 ;1 machine cycle

REPEAT: MOV R1, #250 ;1 machine cycleAGAIN: MOV R2, #250 ;1 machine cycleHERE: NOP ;1 machine cycle

NOP ;1 machine cycleDJNZ R2, HERE ;2 machine cycleDJNZ R1, AGAIN ;2 machine cycleDJNZ R0, REPEAT ;2 machine cycle

RET ;2 machine cycle

END

(For the LED blinking code, you might not be able to observe the response of I/O ports

by using 8952Simulator program because of 8952Simulator cant simulate the real timedelay, and you might wait for long time to count a second delay.)

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