Other popular Microcontrollers are Hitachi H8, Super Hitachi SH7xxx, Mitsubishi 740, 7700; NS COP8, Toshiba TLCS 900S, TI MSP 430.
Used in Digital Television, HDTV Decoders, Set-top Boxes, DVD Players, Web Phones and Video Conferencing.
Classification of Embedded SystemsThree Types of Embedded Systems are :(1) Small Scale(2) Medium Scale(3) Sophisticated
Small Scale Embedded Systems Designed with a single 8 or 16 bit µC. Little Hardware & Softwarecomplexities. Involves Board level design. May be Battery Operated. Programming Tools Needed:Editor, Assembler, Cross Assemblerspecific to µC or µP used.
Medium Scale Embedded Systems Designed with Single or a few 16-32Bit µC or DSP or RISC Computer, Hardware & Software Complexities Programming Tools: RTOS, SourceCode Engg. Tools, Simulator,Debugger, IDE. May employ readily available ASSPand IP for various functions*
Sophisticated Embedded Systems Have enormous H/W and S/W complexities, may needscalable or configurable processors and PLA Used for cutting edge application that needs H/W &S/W Co-design and integration in final system Constrained by processing speed available in theirHardware Certain S/W functions implemented in H/W* to obtainadditional speed by saving execution time. Development Tools for such systems may not bereadily available at a reasonable cost or may not beavailable at all
Processor Types Used in NewEmbedded Designs0.0%10.0%20.0%30.0%40.0%50.0%60.0%4-bit 8-bit 16-bit 32-bit 64-bit Special1998-19991999-2000
Selection of a Processor Instruction Set, Pipelining, Super ScalarExecution. Data Bus Width (8-16-32 Bits) for Arithmetic. Floating Point Coprocessor, Cache Memory On-chip peripheral devices, Clock Frequency, Availability of Retarget-able Compiler andHardware Software Co-design Tools Power Saving Modes available Cost [Components, Development tools, NRE]
Types of Processors used in Emb.Systems General Purpose Processor (GPP): Microprocessor Micro-controller Digital Signal Processor Embedded Processor Application Specific System Processor(ASSP) Multiprocessor Systems using GPP Application Specific Instruction Processor(ASIP)
Microprocessor (µP): Single VLSI Chip having CPU and (may have)Cache memory, Floating point ArithmeticCoprocessor, Pipelining Architecture toprocess instructions faster. CPU Instruction Set supports ALU operations,Data Transfer and Stack operations, Inputand Output, Program Control, Sequencingand Supervisory operations Software located in external memory Chips
Examples- MicroprocessorsIntel 8085Intel 8086/ 888 Bit16 bitSimple controlApplicationsIntel 80386Intel 8048632 bit Graphics Accelerator,Network InterfacecardPentium 64 bit Encryption Enginewith 0.464 Gbps dataratePowerPCMPC 82332 Bit Floating PtCoprocessor, USB,IrDA,
Microcontrollers Contains ROM, RAM Memories onChip Enhanced Input Output capabilities Limited Computational Abilities More Functional Units on Chip:Timers, Watchdog Timer, InterruptController, UART, Parallel I/O Ports,A/D Converter andPWM Circuit for D/A converters
Functional Circuits in a Chip or Core of MicrocontrollerProcessor ROM/ EPROM I/O PortsControls andInterfacesDataandStackRAMTimersExternal MemoryInterfaceSerial UARTA/D ConverterInterruptControllerPWM for D/AWatchdogTimer
Embedded ProcessorSpecially designed µC / µP with:(1) Fast Context Switching and thus lower latenciesof the task in complex real time applications(2) Atomic ALU Operations and thus no shared dataproblem(3) RISC Core for fast, more precise and intensivecalculations by embedded software Needed in Real time Imageprocessing and AerodynamicsApplications
Digital Signal Processor Computational capabilities of a µP Has Multiply – Accumulate (MAC) Units Very Large Instruction Word Processes Single Instruction MultipleData(SIMD) Fast processing of Discrete CosineTransforms and Inverse (IDCT) algorithmsin Image Processing, Multimedia, Audio,Video, HDTV, DSP Modems and TelecomProcessing Systems
Examples - DSPTMS 320C6211 Texas InstrumentsSHARC Analog Devices5600xx Motorola
Application Specific SystemProcessor (ASSP) Dedicated to perform specific tasks in H/WLike Provides Faster Solution using a single Chip Configured & Interfaced with the rest of ES.Target Application Examples: Video Compression & Decompression (MPEG) Encryption and Decryption Implementations Serial to Ethernet Converter Application
Compression & DecompressionApplication in MPEG2 or MPEG4 Standards Compression of Video signal is done beforestoring or transmitting. Decompression isdone before retrieving or receiving thesesignals If embedded Software is run on GPP,separate DSP(s) are required to achievereal time processing. A single dedicatedASSP processor provides a faster solution.
Encryption & Decryption Applications When 2 Systems needs data communicationson a common bus and protocol, EmbeddedSoftware (with some RTOS feature) may takelonger time than a hardware based approach ASSP Processor (W3100) from i2Chip has, forexample TCP, UDP, IP, ARP, Ethernet 10/100Media Access Control (MAC) Provides RTOS less, Internet Connectivity inH/W 5 times faster than a GPP based softwaresolution
Serial to Ethernet Converter Application IIM 7100 processes data in Real Timeby hardware protocol stack Requires no change in ApplicationFirmware Provides economical and smallestRTOS solution.
Multiple Processor System using GPP Multiple GPP are used in MobilePhone. Tasks performed are: Speech signal compression and coding Dialing Modulating & transmitting Demodulating and Receiving Signal decoding and Decompression interface to LCD display and Keypad SMS protocol based messaging anddisplays
Multiple Processors in VideoConferencing Image Pixels are just 144 x 176 as against525 x 625 pixel in video picture on TV. 30 Samples of Images have to be taken in asecond 144 x 176 x 30 = 760320 Pixels per secondare to be processed by Compression beforetransmission A single DSP does not suffice. Multiple DSP(s)are needed to process images during VideoConferencing in real time.
Application Specific InstructionProcessor-ASIP For many Applications, the GPP coresmay not suffice. For examples: Security Applications, Smart Cards, Video games, Palmtopcomputers, Cell phones, MobileInternet, Satellite Missile Systems Gbps Transceivers and Gbps LANsystems
Application Specific InstructionProcessor-ASIP ‘Special Processing Units’ needed in a VLSIdesigned Circuit to function as a Processor,called Application Specific InstructionProcessors (ASIP) Both the Configurable processor (FPGA cumASIP) and Non-configurable processors (DSP,µP or µC) might be needed on a chip. Examples: (1) Cell phone(2) ASIP for HDTV to process an image with1920 x 1020 pixels on TV screen.