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ELE492 – Embedded System Design

Class 1

6/27/06

Eugene Chabot

Outline

� Overview of microcontrollers

� Definition of embedded systems

� Examples of embedded systems

� Development Tools

� Creating a MPLAB project

� Building a basic PIC circuit

ENIAC (electronic numerical integrator and computer)

� first electronic digital computer

Source: ftp.arl.army.mil

Intel 4004

� Integrated

Electronics

� Intel was well

known for RAM technology

� Developed 4004 for

Busicom, which wanted it to replace ASICs in

their calculatorSource: en.wikipedia.org

� Executed programs stored in an

external memory

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What is a microcontroller?

� Similar to a microprocessor

� CPU executes programs

� Programs stored in a RAM or ROM

� TI called it a computer-on-a-chip

� Microprocessor requires external parts:

� Memory

� ‘Glue logic’ – ex. address decoder and buffer chips

� Peripheral chips

Microprocessor vs Microcontroller

vs

Why do we use them?

� Inexpensive (all on one IC) VLSI design

� Small footprint

� Low number of connections

� Resources fit for application

� Faster time to market (compared to custom ICs)

What type of microcontrollers are out there?

� Intel (4004 in ~1970,8051 in ~1980)� 8051 architecture widely produced today

� Zilog (Z8,Z80 derivatives)� Used in the 1970’s for home computers

� Architecture is still used today

� Motorola (68HC11) –phased out for other product lines

� Microchip (division acquired from GI in 1989)

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Microchip

� Major player

� 4 billionth PIC sold last year

� Success attributed to:

� Low cost

� Many peripherals

� Development tools

� Lots of documentation

Microchip (Cont’d)

� PIC – Programmable Intelligent Computer

# instr# pinsSeriesClass

7718-80PIC18High Perf.

358-64PIC12,PIC16Mid-Range

336-28PIC10,PIC12,PIC16

Baseline

Microchip (Cont’d)

� Harvard Architecture – separation of data and program memory

� RISC vs CISC

What is an Embedded System?

� A microprocessor (or microcontroller) based system designed to perform one or more specific tasks.

� “Any mechanical or electrical system that is controlled by a computer working as part of an overall system is called an embedded system.” –Steven Barrett

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Examples of Embedded Systems

Microwaves, toasters, stoves, alarm clocks, remote controls, cell phones, thermostat control, car control systems (ABS, cruise control, navigation systems, radio,…), computer components, network routers/firewalls, copiers, printers, oscilloscopes, medical equipment, …

Special considerations of ES

� Real-Time Execution

� Development and testing environment

� Power Consumption

� User Interface

� Manufacturing Cost

� Limited Memory

� Hardware/software trade-offs

Development Tools

� PIC 18F452 (40 pin DIP)

� Up to 40MHz clock operation (10MIPS)

� 32K ROM (16K Single Word Instructions)

� 1.5KB RAM

� 256Bytes of EEPROM

� 8 10bit D/A converters, Serial, PWM, etc

Development Tools (Cont’d)

� MPLAB IDE

� Program

� Compile

� Simulate

� Debug

� Download

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Development Tools (Cont’d)

� PICSTART+

� ZIF Socket

� Serial

� MCP

� ICSP

� USB

Source: www.olimex.com

Source: www.microchip.com

Development Tools (Cont’d)

� ICD2

� Program

� Erase

� Debug

� USB/Serial

� ICSP only

Source: www.olimex.com

Development Tools (Cont’d)

� Ceramic Resonator

� 4MHz clock input

� Includes internal

capacitors

� Works when hooked up

in either direction

CLK

GN

D

CLK

Development Tools (Cont’d)

� 5V Regulator (7805)

� Connect 9V battery

� Use Caps to clean up power

on power supplies or long

traces

In (9

V)

GN

D

Out (5

V)

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Schematic

PIC18F452

ICSP

Header