Cecs285 Lecture1-Embedded Systems and Embedded Programming

7/30/2019 Cecs285 Lecture1-Embedded Systems and Embedded Programming

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Embedded Systems and the 8051Microcontroller

By Dr. Min He.


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Overview

Introducing Embedded Systems

Difference between Software Development forDesktop and Embedded Systems

The Process of Developing an EmbeddedSystem

Embedded Software Development Tool Chain


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Introducing Embedded Systems

Embedded system: any device thatincludes a programmable computer but

is not itself a general-purpose computer.

Take advantage of applicationcharacteristics to optimize the design:

dont need all the general-purpose bells

and whistles.


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Other Definitions

Embedded Systems are computers lodged inother devices where the presence of thecomputers is not immediately obvious.Computer Architecture A Quantitative

Approach A special-purpose computer system designed

to perform one or a few dedicated functions,often with real-time constraints. It is usuallyembedded

as part of a complete deviceincluding hardware and mechanical parts. --Wikipedia


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Embedded Systems are Everywhere

Personal digital

assistant

(PDA).

Printer.

Cell phone.

Automobile:engine, brakes,

dash, etc.

Television.

Household

appliances. PC keyboard

(scans keys).

And more


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Microwave

Microcontroller: 16 or

32 bit

Used to control theclock/timer and the

on/off cycles of the

different functions like

the Defrost or cookingpower.

CECS347 Embedded Processors 6


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Digital Photo Frame

32-bit RISC processor

(based off ARM)

Image rendering andvideo decoding

together with provision

for touch screen

interfaces.



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Smartphone and Handheld Games

32-bit ARM7TDMI Processor

Plays computer games

Microprocessor: 32 bit

Cortex- M3 : The ARMprocessor

Two features that may make it

desirable for the lower two

devices include that it has 32levels of interrupt priority and 4

GB of addressable memory



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Universal Remote Control

8-bit Microprocessor

Learning capabilitycopies functions from

original remotes



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Product: Sonicare Elitetoothbrush.

Microprocessor: 8-bit

Has a programmablespeed control, timer,

and charge gauge


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Product: Any PCMouse, Keyboard, or

USB Device

Microprocessor:

8-bit Microcontroller

Inside view of a Microsoft Mouse


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Product: AnyPrinter

Microprocessor:Intel, Motorola, or

ARM 32-bit RISC


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Product:Vendo Vue

40 vending

machine.

Microprocessor:Two 16-bit Hitachi

H8/300H

ProcessorsA robot hand

dispenses items


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Product: Pavion

Portable GPSNavigation &

Multimedia System

Microprocessor:ARM , DSP

OS: Windows CE

Also plays MP3s and

Videos


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Product: Dresser Wayne Ovation

iX Gas Pump

Microprocessor:

Marvel Xscale (ARM)

OS: Windows CE

Displays video ads &

is networked to a gas stations

back office computer system.

Also has remote maintenance

features.


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Product: Bernina Artista

200 Sewing Machine

Microprocessor:

Marvel StrongARM

OS: Windows CE

Can download new images

from the internet and sew

them


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Difference Between Software Development

for Desktop and Embedded Systems

Desktop Embedded Systems

The same desktop run many

different programs.

The vast majority of embedded

systems are required to run only

one program.

User program and the required

data are loaded from disk to

RAM when user need to run it

and removed from RAM when

the program is done.

The program will start running

from ROM when the

microcontroller is powered up

until power is turned off.

As a consequence, the simplest architecture in an embedded

system is typically a form of Super Loop.


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A Simple Super Loop Demonstration

void main (void)

{

// Prepare to run function X

X_Init();

while (1) // for ever (Super Loop)

{

X();

}}


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The Process of Developing an

Embedded System

Edit source files on host machines

Cross-compile, link for target on hostmachine

Simulate and test on host machine Building embedded hardware

Getting the embedded software into thetarget system

Test on target machine


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Embedded Software Development

Tool Chain

Cross-compiler/Assembler vs. native tool Host and target machine

Linker/Locators for Embedded Software

Simulate and test on host machine

Getting embedded software into the targetsystems

*Tool chain: a set of tools that is compatiblewith the target machine and is used tosupport the whole development process forembedded software.


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Cross-Compiler, Cross-Assembler

Host Machine vs. Target Machine Host machine: a computer system on

which all the programming tools run.

Target machine: the system that is shipped

to customers.

Cross-compiler/assembler:A compiler/assembler that runs on your

host system but produces the binaryinstructions that will be understood byyour target microprocessor.


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Native Tool ChainABBOTT.Cint idunno;whosonfirst(idunno)

Compiler

Linker

1547

Loader

COSTELLO.C

int whosonfirst (int x){

}

ABBOTT.OBJ

MOVE R1, (idunno);CALL whosonfirst

COSTELLO.OBJ

whosonfirst:

Compiler

HAHAHA.EXE

MOVE R1, 2388CALL 1547MOV R1, R5(value of idunno)2388

HAHAHA.EXE

MOVE R1, 22388CALL 21547MOV R1, R5(value of idunno)

Memory

21547

22388

20000


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Tool Chain for Building Embedded Software

C and C++ files

Cross-compiler

Object files

(may be any format)

Linker/locator

Executable file(may be of any of various standard formats)

Assembly files

Cross-assembler

Object files

(may be any format)

Target System

Operationson

thehost

Executable file is copied to target.


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Reference Materials

An Embedded Software Primer, by David E.Simon, ISBN: 020161569X, Chapter 9 & 10.

Cecs285 Lecture1-Embedded Systems and Embedded Programming

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