May 16, 2005 Department of Computer Sciences & Engineering, Shiraz University

Embedded SystemsMicrocontrollers & Embedded Processors

An Overview

By: Ramtin Raji Kermani

Junior student of Computer Hardware Eng.

Spring 2005

“In the name of God”

Scientific Group of CSE Presents :

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

Embedded Systems

What is an Embedded System? Where are Embedded Systems used? Typical Embedded Systems Hardware Embedded OS and Software Microcontrollers The 8051 Microcontroller A simple project using AT89C51 References

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

What is and Embedded System?

A specialized computer system that is part of a larger system or machine. Typically, an embedded system is housed on a single microprocessor board with the programs stored in ROM. Virtually all appliances that have a digital interface -- watches, microwaves, VCRs, cars -- utilize embedded systems. Some embedded systems include an operating system, but many are so specialized that the entire logic can be implemented as a single program. (Definition from wikipedia.com)

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

What is and Embedded System?

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

ES, Other definitions

A special purpose computer built into a larger device. Special purpose:

- Embedded systems have a (more or less) well-defined purpose - Contrast with: general purpose computers (PCs etc) - Both hardware and software is tailored to application(s), which are

well defined - However, re-programmability is a requirement

Built into a larger device: ESs are (usually) part of a larger device, augmenting its capabilities

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

ES, Other definitions

Any device that includes a programmable computer but is not itself a general-purpose computer.

Anything that uses a computer but does not look like one.

The microprocessor in an embedded system is like an electric motor in a washing machine.

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

ES Types & Characteristics

Types of Processing unit: Hardwired logic Programmable units

ES Characteristics: Efficiently Cost effective Power efficiently Real-time Predictability

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

ES: History and Solutions

A very little history: ;) The first Embedded System: Apollo Guidance Computer.

Embedded Systems Solutions: Microcontrollers Embedded Processors Digital Signal processors

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

Where are Embedded Systems used?

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

Where are Embedded Systems used?

Signal processing systems Real-time video, DVD players, Medical equipment.

Distributed control Network routers, switches, firewalls, mass transit systems, Elevators

“Small” systems Mobile phones, pagers, home appliances, toys, smartcards, MP3

players, PDAs, digital cameras, sensors, pc keyboard & mouse Modern cars: Up to 100 or more processors

Engine control unit ABS systems (Anti Lock Brake systems) Emissions control Diagnostics and Security systems Accessories (doors, windows etc)

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

Typical Embedded Systems Hardware

Commercial off-the-shelf components (COTS) e.g. wireless radios, sensors, I/O devices Cheap

Application-Specific ICs (ASICs) ICs tailored to meet application needs Good performance for their intended task(s) Original ESs were ASICs only

Domain-specific processors DSPs Microcontrollers

Microprocessors General Purpose Processors

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

New trends in ES HW

Systems-on-chip Usual (or desired) specs:

32-bit RISC CPU Built-in interfaces to RAM and ROM Built-in DMA, interrupt and timing controllers Built-in interfaces to disk or flash memory Built-in Ethernet/802.11 interfaces Built-in LCD/CRT interfaces

New SOCs appearing almost every week! Examples

Intel StrongARM SA-1110 Motorola PowerPC MPC823e NEC VR4181 Many, many more

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

Embedded OS and Software

Principal role: ‘Not transformation of data but interaction with physical world’

Acquires properties of physical world Takes time Consumes power Does not terminate (unless it fails)

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

Embedded Operating Systems:

Office-style OSes PalmOS WindowsCE

RTOSes VxWorks QNX

Linux Linux is already ubiquitous

Hundreds of different devices are using it http://www.linuxdevices.com/articles/AT4936596231.html

Numerous commercial + open source products Mobile OS

Symbian Others

TinyOS

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

What is a Microcontroller?

A microcontroller is an entire computer manufactured on a single chip.

They have a high concentration of on-chip facilities such as serial ports, parallel input/output ports, timers, counters, interrupt control, analog-to-digital converters, random access memory, read only memory, etc.

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

The 8051 Microcontroller:

The 8051 is the first microcontroller of the MCS-51 family introduced by Intel Corporation at the end of the 1970’s.

The 8051 family characteristics: 4K Bytes ROM 128 Bytes RAM two timer/counters (16 bit) A serial port 4 general purpose parallel input/output port Interrupt controller

The 8051 can address 64K of external data memory and 64K of External program memory.

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

Microcontroller 8051 internal Architecture

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

8051 pin description

8051 other family members: 8751 (has EPROM) 8951 (has EEPROM)

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

A simple project using AT89C51

Here we’ve designed, built and programmed a digital BCD counter that counts from 0 to 9 on a 7Segment display.

We use register A as Accumulator, in each delayed cycle the accumulator increments by one and result is showed on the 7segment display.

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

A simple project using AT89C51

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

References

Web References: www.google.com http://www.embedded.com http://www.wikipedia.org/wiki/Embedded_system http://www.linuxdevices.com Mani Srivastava’s EE202A class

http://nesl.ee.ucla.edu/courses/ee202a/2002f Edward Lee, “Embedded Software”

http://citeseer.nj.nec.com/497408.html

Books: The 8051 Microcontroller and Embedded Systems: Mazidi, M.A. Microprocessors: Uffenbeck, john میکروکنترولر 201 با عملی . 8051مدار انتشارات خاکپور، ف ،

صفار

Department of Computer Sciences & Engineering, Shiraz University

May 16, 2005

At the End …

Thanks for your Attention … ;)

Ramtin Raji Kermani

Spring 2005