Top Banner
Embedded Systems - Introduction www.Bookspar.com | Website for Students | VTU - Notes - Question Papers
53

Embedded Systems - Introduction

Jan 07, 2016

Download

Documents

tadhg

Embedded Systems - Introduction. System Definition A way of working, organizing or performing one or many tasks according to a fixed set of rules, program or plan. System Definition An arrangement in which all units assemble and work together according to a program or plan. - PowerPoint PPT Presentation
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: Embedded Systems - Introduction

Embedded Systems - Introduction

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 2: Embedded Systems - Introduction

System Definition

A way of working, organizing or performing one or many tasks according to a fixed set of rules, program or plan.

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 3: Embedded Systems - Introduction

System Definition

An arrangement in which all units assemble and work together according to a program or plan.

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 4: Embedded Systems - Introduction

Examples of Systems

Time display system – A watch

Automatic cloth washing system – Awashing machine

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 5: Embedded Systems - Introduction

Embedded System Definition:

1. “An embedded system is a system that has software embedded into computer-hardware, which makes a system dedicated for an application (s) or specific part of an application or product or part of a larger system.”

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 6: Embedded Systems - Introduction

2. “An embedded system is one that has a dedicated purpose software embedded in a computer hardware.”

Contd..

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 7: Embedded Systems - Introduction

3. “It is any device that includes programmable computer but is not itself intended to be a general purpose computer.” –Wayne Wolf, Ref: 61

Contd..

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 8: Embedded Systems - Introduction

4. “Embedded Systems are the electronic systems that contain a microprocessor or amicrocontroller, but we do not think of them as computers– the computer is hidden or embedded in the system.” – Todd D. Morton, Ref: 38

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 9: Embedded Systems - Introduction

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 10: Embedded Systems - Introduction

Let’s consider a Computer

A computer is a system that has the following or more components.

• A microprocessor

• A large memory comprising the followingtwo kinds: (a) Primary memory (semiconductormemories - RAM, ROM and fast accessiblecaches)

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 11: Embedded Systems - Introduction

Computer

(b) Secondary memory [(magnetic memorylocated in hard disks, diskettes and cartridgetapes, optical memory in CD-ROM ormemory stick (in mobile computer)] usingwhich different user programs can load intothe primary memory and can be run.

• I/O units such as touch screen, modem, faxcum modem etc.

Contd..

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 12: Embedded Systems - Introduction

• Input units such as keyboard, mouse, digitizer, scanner, etc.

• Output units like LCD screen, video monitor, printer, etc.

• Networking units like Ethernet card, front-end processor-based server, bus drivers, etc.

Contd..

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 13: Embedded Systems - Introduction

•Operating system (OS).

• General purpose user interfaces and application software, mostly in secondary memory

Contd..

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 14: Embedded Systems - Introduction

Three main embedded components in an Embedded System

1.Embeds hardware to give computer like functionalities.

2.Embeds main application software generally into flash or ROM and the application software performs concurrently the number of tasks.

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 15: Embedded Systems - Introduction

3. Embeds a real time operating system ( RTOS), which supervises the application software tasks running on the hardware and organizes the accesses to system resources according to priorities and timing constraints of tasks in the system.

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 16: Embedded Systems - Introduction

Real Time Operating System(RTOS)

An RTOS is an OS for response time controlled and event controlled processes.

Software for a large number of small-scale embedded systems use no RTOS and these functions are incorporated into the application software.

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 17: Embedded Systems - Introduction

• Enables execution of concurrent processes or threads or tasks

• Provides a mechanism to let the processor run each process as per scheduling and to do context-switch between the various processes (threads or tasks)

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 18: Embedded Systems - Introduction

• RTOS sets the rules during execution

RTOS is necessary for large-scale embedded systems. It is essential when

• I/O management with devices, files and mail-boxes becomes simple using a RTOS.

• scheduling of multiple processes and devices

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 19: Embedded Systems - Introduction

RTOS v/s General Purpose OS 

1. Determinism 

2.   Task Scheduling

3.   Preemptive kernel 4.   Priority Inversion

5. Usage www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 20: Embedded Systems - Introduction

Sophisticated Embedded SystemCharacteristics

(1) Dedicated functions

(2) Dedicated complex algorithms

(3)Dedicated (GUIs) and other user interfaces for the application

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 21: Embedded Systems - Introduction

(4) Real time operations— Defines the ways in which the system works, reacts to the events and interrupts, schedules the system functioning in real time and executes by following a plan to control the latencies and to meet the deadlines.

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 22: Embedded Systems - Introduction

(5) Multi-rate operations -Different operations may take place at distinct rates. For example, the audio, video, network data or stream and events have the different rates and time constraints to finish associated processes..

Contd..

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 23: Embedded Systems - Introduction

Constraints of an Embedded System Design

• Available system-memory

• Available processor speed

• Limited power dissipation when running the system continuously in cycles of the system start, wait for event, wake-up and run, sleep and stop.

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 24: Embedded Systems - Introduction

• Performance

• power

• size

• non-recurring design cost, and manufacturing costs

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 25: Embedded Systems - Introduction

PROCESSOR IN EMBEDDEDSYSTEM

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

•Processor is the heart of embedded system

• Processor has two essential units:

Control Unit(CU) Execution Unit(EU)

Page 26: Embedded Systems - Introduction

• Program Flow and data path (CU) Control Unit—includes a fetch unit for fetching instructions from the memory.

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 27: Embedded Systems - Introduction

• Execution Unit (EU) —includes circuits for arithmetic and logical unit (ALU), and for instructions for a program control task, say, data transfer instructions, halt, interrupt, or jump to another set of instructions or call to another routine or sleep or reset.

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 28: Embedded Systems - Introduction

A Processor is in the form of an IC or it could be in core form in an Application Specific Integrated Circuit (ASIC) or System on Chip (SoC).

An embedded processor chip or core can be one of the following:

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 29: Embedded Systems - Introduction

1. General Purpose Processor (GPP) : instruction set designed not specific to the applications.

example: Microprocessor

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 30: Embedded Systems - Introduction

• A Microprocessor is a single VLSI chip that has a CPU and has some other units such as caches, pipelining and super scaling units.

• is an essential part of a computing system.

Intel 80x86 family, ARM, 68HCxxx family.

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 31: Embedded Systems - Introduction

2. Application Specific Instruction-set Processor (ASIP): is a processor with instruction set designed for specific applications on a VLSI chip.

Examples: micro controller embedded micro controller DSP and media processor

Network processor IO processor or

domain-specific programmable processor

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 32: Embedded Systems - Introduction

• A Microcontroller is an integrated chip (IC) that has a processor, memory and several other hardware units in it such as timers, watchdog timer, interrupt controller, ADC or PWM . • is an essential component of a control or communication circuit.

8051, 8051 MX, 68HC11xx, PIC18

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 33: Embedded Systems - Introduction

Various functional circuits in a microcontroller chip:

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 34: Embedded Systems - Introduction

Commonly used exemplary microcontrollers in small scale embedded Systems

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 35: Embedded Systems - Introduction

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 36: Embedded Systems - Introduction

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 37: Embedded Systems - Introduction

3. Single Purpose Processors or additional processors:

Examples: • Coprocessors: used for graphic processing, floating point processing, encrypting, deciphering, discrete cosine transformation and inverse transformation on TCP/IP protocol stacking and networking connecting functions.

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 38: Embedded Systems - Introduction

• Accelerator: Java codes accelerator

• Controllers: for peripherals, direct memory access and buses

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 39: Embedded Systems - Introduction

4. GPP or ASIP cores integrated into either an ASIC or VLSI circuit or a Field Programmable Gate Array (FPGA) core integrated with processor units in a VLSI chip.

5. Application Specific system Processor (ASSP)

6.Multi core processors or multi processors. www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 40: Embedded Systems - Introduction

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 41: Embedded Systems - Introduction

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 42: Embedded Systems - Introduction

Embedded hardware units and Devices in a system

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

1. Power source

• A power supply source or charge pump is essential in every system.

• The systems which do not have power supply of their own are powered by the use of charge pumps or they connect to external power supply.

Page 43: Embedded Systems - Introduction

2. Clock Oscillator circuit and Clocking units:

• the clock controls the time for executing an instruction.• also controls the various clocking requirements of CPU, of system timers, CPU machine cycles. • A processor needs a clock oscillator circuit to establish a reference frequency used for timing purposes.

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 44: Embedded Systems - Introduction

3. System timers and Real-Time Clock(RTC):

• to schedule the various tasks and for real time programming , an RTC or system clock is needed.

• A timer circuit is configured as system clock , which ticks and generates interrupts periodically.

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 45: Embedded Systems - Introduction

4. Reset circuit , Power-up Reset and Watchdog timer Reset :

• Reset circuit can change the Program Counter (PC) to a power-up default value.• A program that is reset and runs on a power-up can be one of the following: i) system program that executes from the beginning.ii) A system boot-up programiii) A system initialization program

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 46: Embedded Systems - Introduction

Reset: Processor begins the processing of instructions from a starting address.

The reset circuit can be activated by any one of the following:1. software instruction2. time-out by a programmable timer known as watchdog timer.3. a clock monitor detecting a slow down below certain frequencies.

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 47: Embedded Systems - Introduction

Watchdog Timer:

A timing device that resets the system after a predefined timeout.

Helps in rescuing the system if a fault develops.

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 48: Embedded Systems - Introduction

Memory:a. Functions Assigned to the ROM orEPROM or Flash

1. Storing 'Application' program from wherethe processor fetches the instruction codes.

2. Storing codes for system booting,initializing, Initial input data and Strings.

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 49: Embedded Systems - Introduction

3. Storing Codes for RTOS.

4. Storing Pointers (addresses) of variousservice routines.

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers | RESULTS |NEWS | FORUM

Page 50: Embedded Systems - Introduction

b. Functions Assigned to the Internal, External and Buffer RAM:

1.Storing the variables during program run,2. Storing the stacks,3. Storing input or output buffers for example,for speech or image .

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 51: Embedded Systems - Introduction

c. Functions Assigned to the EEPROM or Flash : • Storing non-volatile results of processing

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 52: Embedded Systems - Introduction

d. Functions Assigned to the Caches: 1. Storing copies of the instructions, data andbranch-transfer instructions in advancefrom external memories and

2. Storing temporarily the results in write back caches during fast processing

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers

Page 53: Embedded Systems - Introduction

e. Functions Assigned to Memory Stick:

It stores high definition video, images, songs, Or speeches after a suitable format compressionAnd stores large persistent data.

in digital camera, mobile computing system

www.Bookspar.com | Website for Students | VTU - Notes - Question

Papers