Introduction to Embedded Systems

What is an Embedded System? Electronic devices that incorporate a microprocessor or microcontroller within their implementation. Microprocessor of embedded system is hidden from user. No Mouse, Kbd, monitor, etc.

Embedded Systems Applications AerospaceNavigation systems, automatic landing systems, flight attitude controls, engine controls, space exploration (e.g.. The mars pathfinder) AutomotiveFuel injection control, passenger environmental controls, anti-locking braking systems, air bag controls, GPS mapping, cruise control Children's toysVideo games, MindStone system CommunicationsSatellites, network routers, switches, hubs

Embedded Systems Applications Computer PeripheralsPrinters, scanners, keyboards, displays, modems, hard disk drives, CD-ROM drives, USB HomeDishwashers, microwave ovens, VCR’s, DVD, televisions, stereos, fire/security alarm systems, lawn sprinkler controls, thermostats, digital cameras, clock radios, cell phones IndustrialElevator controls, surveillance systems, robots InstrumentationData collection, oscilloscopes, signal generators, signal analyzers, power supplies

Embedded Systems Applications MedicalCT, One touch glucose meter, almost all medical facility Office AutomationFAX machines, copiers, telephones, PersonalPDA’s, pagers, cell phones, video games, Ipod, MP3 players

Embedded Market Embedded:desktop = 100:1 Average #embedded processors in the resident home estimated about 50

Embedded System

CPU and Software Memory Storage: ROM, RAM, PROM, EPROM Input: knobs, buttons, probes, sensors, A/D communications signals, panels Output: LCD display, microwave radiation, A/D communication signals Outputs = functions (inputs, elapsed time, …)

Microprocessors in Embedded Systems ProcessorBus Width Largest External Memory Internal peripherals Speed (MIPS) Zilog Z8 family8 64KB on others2 timers1 Intel 8051 family864 KB program + 64 KB data 3 timers + 1 serial port 1 Intel MB3 timers + 2 DMA channels 2 Intel family 1664 MB3 timers + 2 DMA channels + various others 5 Motorola family 324 GB Varying10 Motorola Power PC family 3264 MBMany75

Common Design Criterion Production cost constraints Processing power(limited) Memory constraints(limited) Development cost(low) Number of units Expected life time( may not be long) Reliability

Design Criterion Processor4 or 8-bit16-bit32 or 64-bit Memory < 16KB 64 KB~1 MB > 1 MB Development Cost < $100,000$100,000 ~ $1,000,000 > $1,000,000 Production Cost < $10$10 ~ $1,000> $1,000 # Units< – 10,000 > 10,000 Expected lifetime < yearsyearsdecades ReliabilitylowMediumHigh

C for embedded software The most popular language for embedded systems ( over 80%) A high level language Compact, efficient code for almost all processors Both high-level and low-level features Direct hardware control, without losing the benefits of a high-level language Appropriate for 8-bit to 64-bit processors For systems with bytes, KB, MB of memory

Typical Hardware Microprocessor: execute code Memory: ROM, RAM, PROM, EPROM, Flash Embedded systems do not have the following - a keyboard - a screen - a disk drive - CD, speakers, microphones, diskettes, modems Embedded systems have: serial port, network interface, sensors, AD/DA

Design Goal of Embedded System Mission critical and life-threatening 24/7/365 and can’t reboot at all No human intervention Multitasking and scheduling Optimized I/O by Assembly Language Limits, Inaccuracies of Fixed Precision Consumer market: Minimize Manufacturing Cost Fast time to market required No chance for future modification

Design Goal of Embedded System Handle a lot of volume of data in a short period of time React to external events quickly Setting up equipment to test embedded software Without a screen or keyboard, finding out what the software is doing wrong Must be able to handle any situation without human intervention Memory is limited on embedded systems, and you must make the software and the data fit into whatever memory allows

Design Goal of Embedded System You will need special tools to get your software into embedded systems (burner) Portable systems must run on battery power, and the software in these systems must conserve power Embedded systems have a microprocessor and a memory. Some have a serial port or a network connection. They usually do not have keyboards, screens, or disk drives.