Embedded System

What is an Embedded System?• Computing systems embedded within electronic

devices• Hard to define– Nearly any computing system other than a desktop

computer– “A computer that is a component in a larger system,

and is not visible as a computer to a user of that system.”

– “A programmable component of subsystem providing some intelligence functions to the system of which it is a part.”

What is an Embedded System?• A microcontroller based system.• Built into a device to control a function or a range of functions.• Not designed to be programmed by the end-user (like a PC).• Executes an in-built single program repeatedly.• Tight coupling between hardware and software.• Designed to work in highly constrained environments.• Low cost, low power, small, fast, etc.• Reactive and real-time• Continually reacts to changes in the system’s environment• Must compute certain results in real-time without delay

Embedded Systems• Automotive systems• Airplanes• Toys• Medical Devices

Example Embedded Systems

Microcontroller Example

Microprocessor vs. Microcontroller

Pin Details of 8051

Microcontroller Market• Shipments- > 16 Billion in 2000, 8 bit > 1/2

market• Major Players: – Microchip 16Fxx– Intel 8051– Motorola MC68HCxx– National COP800– SGS/Thomson ST62– Zilog Z86Cxx

Shipments

1990 1992 1994 1996 1998 20000

5000

10000

1990 1992 1994 1996 1998 2000

Worldwide Microcontroller Shipments in Millions of Dollars4-bit

8-bit

16-bit

Programming Languages• ASM– Low level– Full Control

• BASIC, Forth, LOGO– Interpreted– Easy to use– Slow

• C– Most widely used– HiTech C– Microchip C– CCS PIC C

What is the Process ?1. Write you program in MPLAB IDE

• C or ASM

2. Compile your program• CCS C Compiler

3. Transfer your program• Puts HEX file into the PIC• Use PICSTART and MPLAB• “Burns your app into the PIC”

4. Insert your PIC5. Power it Up

AVR Microcontroller

The AVR is a modified Harvard architecture 8-bit RISC single chip microcontroller which was developed by Atmel in 1996. The AVR was one of the first microcontroller families to use on-chip flash memory for program storage, as opposed to one-time programmable ROM, EPROM, or EEPROM used by other microcontrollers at the time.

Introduction

Device overviewThe AVR is a modified Harvard architecture machine where program and data are stored in separate physical memory systems that appear in different address spaces, but having the ability to read data items from program memory using special instructions.

Basic familiesAVRs are generally classified into six broad groups:tinyAVR — the ATtiny series

0.5–8 kB program memory6–32-pin packageLimited peripheral set

megaAVR — the ATmega series 4–256 kB program memory28–100-pin packageExtended instruction set (Multiply instructions and instructions for handling larger program memories)Extensive peripheral set

XMEGA — the ATxmega series 16–384 kB program memory44–64–100-pin package (A4, A3, A1)Extended performance features, such as DMA, "Event System", and cryptography support.Extensive peripheral set with DACs

Application-specific AVR megaAVRs with special features not found on the other members of the AVR family, such as LCD controller, USB controller, advanced PWM, CAN etc.

FPSLIC (AVR with FPGA) FPGA 5K to 40K gatesSRAM for the AVR program code, unlike all other AVRsAVR core can run at up to 50 MHz [5]

32-bit AVRsMain article: AVR32In 2006 Atmel released microcontrollers based on the new, 32-bit, AVR32 architecture. They include SIMD and DSP instructions, along with other audio and video processing features. This 32-bit family of devices is intended to compete with the ARM based processors. The instruction set is similar to other RISC cores, but is not compatible with the original AVR or any of the various ARM cores.

AVR Pin Details