Embedded Systems Overview Prepared by Nisha Sinsinbar Subject: Microcontoller & Interfacing Sub code: EC Department

Embedded Systems Overview  Computing systems are everywhere  Most of us think of “desktop” computers  PC’s  Laptops  Mainframes  Servers  But there’s another type of computing system  Far more common...

Embedded Systems Overview Embedded computing systems –Computing systems embedded within electronic devices –Hard to define. Nearly any computing system other than a desktop computer –Billions of units produced yearly, versus millions of desktop units –Perhaps 50 per household and per automobile Computers are in here... and here... and even here... Lots more of these, though they cost a lot less each.

A “short list” of embedded systems Anti-lock brakes Auto-focus cameras Automatic teller machines Automatic toll systems Automatic transmission Avionic systems Battery chargers Camcorders Cell phones Cell-phone base stations Cordless phones Cruise control Curbside check-in systems Digital cameras Disk drives Electronic card readers Electronic instruments Electronic toys/games Factory control Fax machines Fingerprint identifiers Home security systems Life-support systems Medical testing systems Modems MPEG decoders Network cards Network switches/routers On-board navigation Pagers Photocopiers Point-of-sale systems Portable video games Printers Satellite phones Scanners Smart ovens/dishwashers Speech recognizers Stereo systems Teleconferencing systems Televisions Temperature controllers Theft tracking systems TV set-top boxes VCR’s, DVD players Video game consoles Video phones Washers and dryers

What is an embedded system?  What makes a microcontroller: – Self Contained CPU Memory I/O – Application or Task Specific Not a general-purpose computer Appropriately scaled for the job

Designing Embedded Systems Microcontrollers – Don’t have keyboard and monitor jacks – Must use ports to perform I/O Inputs – to sense things Outputs – to control things Related Component Topics – Common Interfaces – Part Packages

The Atmel AVRTM is a family of 8-bit RISC microcontrollers produced by Atmel. The AVR architecture was conceived by two students at the Norwegian Institute of Technology (NTH) and further refined and developed at Atmel Norway, the Atmel daughter company founded by the two chip architects. History of AVR

Introduction to AVR

AVR Architecture What are the features of RISC? – 1 instruction per clock cycle (pipelined) – Lots of registers: 32 GP registers – Register-to-register operation Variations in the parts: – TINY to MEGA – ATtiny10 Processor has only 8 pins – ATmega128 (128K bytes flash) Processor has 64 pins

AVR Architecture

AVR RISC Architecture Single Cycle Instructions: 8mhz = 8mips. Large register file (32). Every register an accumulator. 3 index register pairs Register & IO are mapped in SRAM space.

13 On Chip Debugger Two Wire Interface

Typical Hardware Support Internal or External Oscillator/Clock Brown Out Detector One or more timers Two or more PWM One or more USART 10 bit ADC Analog Comparator External interrupts

AVR Memory Space Program Flash – Vectors, Code, and (Unchangeable) Constant Data Working Registers – Includes X, Y, and Z registers. I/O Register Space – Includes “named” registers SRAM – Data Space – Runtime Variables and Data – Stack space EEPROM space – For non-volatile but alterable data

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