![Selection of a Processor
Instruction Set, Pipelining, Super Scalar
Execution.
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 and
Hardware Software Co-design Tools
Power Saving Modes available
Cost [Components, Development tools, NRE]](https://image.slidesharecdn.com/39245196-intro-es-iii-130624110517-phpapp02/85/39245196-intro-es-iii-6-320.jpg)
39245196 intro-es-iii
- 1. Classification of Embedded Systems Three Types of Embedded Systems are : (1) Small Scale (2) Medium Scale (3) Sophisticated
- 2. Small Scale Embedded Systems Designed with a single 8 or 16 bit µC. Little Hardware & Software complexities. Involves Board level design. May be Battery Operated. Programming Tools Needed: Editor, Assembler, Cross Assembler specific to µC or µP used.
- 3. Medium Scale Embedded Systems Designed with Single or a few 16-32 Bit µC or DSP or RISC Computer, Hardware & Software Complexities Programming Tools: RTOS, Source Code Engg. Tools, Simulator, Debugger, IDE. May employ readily available ASSP and IP for various functions*
- 4. Sophisticated Embedded Systems Have enormous H/W and S/W complexities, may need scalable 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 their Hardware Certain S/W functions implemented in H/W* to obtain additional speed by saving execution time. Development Tools for such systems may not be readily available at a reasonable cost or may not be available at all
- 5. Processor Types Used in New Embedded Designs 0.0% 10.0% 20.0% 30.0% 40.0% 50.0% 60.0% 4-bit 8-bit 16-bit 32-bit 64-bit Special 1998-1999 1999-2000
- 6. Selection of a Processor Instruction Set, Pipelining, Super Scalar Execution. 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 and Hardware Software Co-design Tools Power Saving Modes available Cost [Components, Development tools, NRE]
- 7. 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)
- 8. Microprocessor (µP): Single VLSI Chip having CPU and (may have) Cache memory, Floating point Arithmetic Coprocessor, Pipelining Architecture to process instructions faster. CPU Instruction Set supports ALU operations, Data Transfer and Stack operations, Input and Output, Program Control, Sequencing and Supervisory operations Software located in external memory Chips
- 9. Examples- Microprocessors Intel 8085 Intel 8086/ 88 8 Bit 16 bit Simple control Applications Intel 80386 Intel 80486 32 bit Graphics Accelerator, Network Interface card Pentium 64 bit Encryption Engine with 0.464 Gbps data rate PowerPC MPC 823 32 Bit Floating Pt Coprocessor, USB, IrDA,
- 10. Microcontrollers Contains ROM, RAM Memories on Chip Enhanced Input Output capabilities Limited Computational Abilities More Functional Units on Chip: Timers, Watchdog Timer, Interrupt Controller, UART, Parallel I/O Ports, A/D Converter and PWM Circuit for D/A converters
- 11. Functional Circuits in a Chip or Core of Microcontroller Processor ROM/ EPROM I/O Ports Controls and Interfaces Data and Stack RAM Timers External Memory Interface Serial UART A/D Converter Interrupt Controller PWM for D/A Watchdog Timer
- 12. Microcontroller Examples 68HC11, HC12 Motorola CISC 8051, 80251 Intel CISC 80186, 80386 Intel CISC PIC 16F84, PIC 16F876 Microchip CISC Enhancemen t of ARM7, ARM9 TI CISC with RISC
- 13. Embedded Processor Specially designed µC / µP with: (1) Fast Context Switching and thus lower latencies of the task in complex real time applications (2) Atomic ALU Operations and thus no shared data problem (3) RISC Core for fast, more precise and intensive calculations by embedded software Needed in Real time Image processing and Aerodynamics Applications
- 14. Examples- Embedded Processors ARM 7 and ARM 9 Image Processing Intel i960 4 Channel DMA Controller
- 15. Digital Signal Processor Computational capabilities of a µP Has Multiply – Accumulate (MAC) Units Very Large Instruction Word Processes Single Instruction Multiple Data(SIMD) Fast processing of Discrete Cosine Transforms and Inverse (IDCT) algorithms in Image Processing, Multimedia, Audio, Video, HDTV, DSP Modems and Telecom Processing Systems
- 16. Examples - DSP TMS 320C6211 Texas Instruments SHARC Analog Devices 5600xx Motorola
- 17. Application Specific System Processor (ASSP) Dedicated to perform specific tasks in H/W Like 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
- 18. Compression & Decompression Application in MPEG2 or MPEG4 Standards Compression of Video signal is done before storing or transmitting. Decompression is done before retrieving or receiving these signals If embedded Software is run on GPP, separate DSP(s) are required to achieve real time processing. A single dedicated ASSP processor provides a faster solution.
- 19. Encryption & Decryption Applications When 2 Systems needs data communications on a common bus and protocol, Embedded Software (with some RTOS feature) may take longer time than a hardware based approach ASSP Processor (W3100) from i2Chip has, for example TCP, UDP, IP, ARP, Ethernet 10/100 Media Access Control (MAC) Provides RTOS less, Internet Connectivity in H/W 5 times faster than a GPP based software solution
- 20. Serial to Ethernet Converter Application IIM 7100 processes data in Real Time by hardware protocol stack Requires no change in Application Firmware Provides economical and smallest RTOS solution.
- 21. Multiple Processor System using GPP Multiple GPP are used in Mobile Phone. 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 and displays
- 22. Multiple Processors in Video Conferencing Image Pixels are just 144 x 176 as against 525 x 625 pixel in video picture on TV. 30 Samples of Images have to be taken in a second 144 x 176 x 30 = 760320 Pixels per second are to be processed by Compression before transmission A single DSP does not suffice. Multiple DSP(s) are needed to process images during Video Conferencing in real time.
- 23. Application Specific Instruction Processor-ASIP For many Applications, the GPP cores may not suffice. For examples: Security Applications, Smart Cards, Video games, Palmtop computers, Cell phones, Mobile Internet, Satellite Missile Systems Gbps Transceivers and Gbps LAN systems
- 24. Application Specific Instruction Processor-ASIP ‘Special Processing Units’ needed in a VLSI designed Circuit to function as a Processor, called Application Specific Instruction Processors (ASIP) Both the Configurable processor (FPGA cum ASIP) 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 with 1920 x 1020 pixels on TV screen.