Winter-Spring 2001Codesign of Embedded Systems1 Introduction to HW/SW Codesign Part of HW/SW Codesign of Embedded Systems Course (CE )

Winter-Spring 2001Codesign of Embedded Systems2 Today programme Introduction to HW/SW Codesign Distinguishing features of electronic systems System-level codesign issues Reference: G. De Micheli, M. Sami, “Hardware/Software Co-design”, NATO ASI Series, Kluwer Academic Publishers, Reference: G. De Micheli, M. Sami, “Hardware/Software Co-design”, NATO ASI Series, Kluwer Academic Publishers, 1996.

Winter-Spring 2001Codesign of Embedded Systems3 Introduction to HW/SW Codesign Distinguishing features of electronic systems

Winter-Spring 2001Codesign of Embedded Systems4 Distinguishing features of electronic systems Application Domain Degree of Programmability Level of Integration Hardware Technology

Winter-Spring 2001Codesign of Embedded Systems5 Application domains General-purpose computing systems Dedicated computing and control systems Emulation and prototyping systems

Winter-Spring 2001Codesign of Embedded Systems6 Application domains (cont’d) GP computing systems Traditional computers End-user can program them Support applications of different kinds Dedicated computing and/or control systems Specific target applications Limited programming access for the user Dedicated software programs Known as Embedded Systems “Control functions” or “Data comm. and processing” or both

Winter-Spring 2001Codesign of Embedded Systems7 Application domains (cont’d) Emulation and prototyping systems Programmable HW technology Hardware configuration by HW compilers (synthesis systems) Specialized users program them Intermediate points of the design and manufacturing of a product

Winter-Spring 2001Codesign of Embedded Systems8 Degree of programmability Programmability at the Application level Instruction level Hardware level

Winter-Spring 2001Codesign of Embedded Systems9 Degree of programmability (cont’d) Application level Most restricted level User have to use specialized language VCR - Automated navigation systems Instruction level Personal computer users Writing, compiling and executing programs Processor architecture defines degree of programmability

Winter-Spring 2001Codesign of Embedded Systems10 Degree of programmability (cont’d) Hardware level Configuring HW after manufacturing Micro-programming: emulation of other ISAs Common for DSPs, not for ISPs (esp. RISC) FPGAs

Winter-Spring 2001Codesign of Embedded Systems11 Degree of programmability (cont’d) Programmability Increases applicability, but not performance Top performance in GP computing: super-scalar RISC architectures Dedicated applications: ASICs Some app. domains (ex. Comm.) ASIPs: specialized instruction-level programmable processors Midway between ASIC and ISP: Performance, Power, Production volume

Winter-Spring 2001Codesign of Embedded Systems12 Technology Digital-system components have Different scale of integration Discrete and integrated components Different fabrication technology Bipolar, CMOS To us, technology affects field-programmability Storing programs in memory Configurable HW One-time configurable Re-configurable

Winter-Spring 2001Codesign of Embedded Systems13 Level of Integration Digital systems are Lumped => System-on-Chip Distributed Advantages of higher integration Higher reliability Lower power budget Increased performance Disadvantages Larger chip sizes. More complex debugging

Winter-Spring 2001Codesign of Embedded Systems14 Introduction to HW/SW Codesign System-level Co-Design Issues

Winter-Spring 2001Codesign of Embedded Systems15 General-purpose computing systems ISP: Primarily in general-purpose computing Codesign of ISP is strange Architectural support for OS Compiler development: Retargetable, Optimizing Codesign areas: organizational choices: pipelines, concurrency, memory hierarchy Instruction-set selection Performance Compatibility

Winter-Spring 2001Codesign of Embedded Systems16 Dedicated computing and control systems Data-processing systems GP DSP / ASIP ASIP Less compatibility, more performance Need for application-specific compilers Retargetable compilers Computer-Aided compiler generation fixed-point arithmetic operations Hence, use assembly Today design time: SW > HW

Winter-Spring 2001Codesign of Embedded Systems17 Dedicated computing … (cont’d) Embedded control systems Sensors MemoryCPU Actuators Hardwired Unit Random Logic Timers A/D D/A Embedded System

Winter-Spring 2001Codesign of Embedded Systems18 Dedicated computing … (cont’d) Control systems Often have a data-processing component Reactive systems RT: hard/soft Timers Safety and reliability more important than performance Safety: Formal verification+ System-level testing Reliability: Redundancy

Winter-Spring 2001Codesign of Embedded Systems19 Emulation and prototyping systems Codesign application 1: SW accelerators/coprocessors Specific operations: floating-point ops. Critical loops: exploiting local parallelism for(j=0; j<N; j++) a[j] = a[j] + b[j]; for(j=1; j<N; j++) a[j] = a[j] + a[j-1]; Coprocessors based on programmable HW Example: PAM (PeRLe-0, PeRLe-1)

Winter-Spring 2001Codesign of Embedded Systems20 Emulation and prototyping systems (cont’d) Major codesign problems: Identifying critical parts of SW Compile critical SW parts for HW emulation Codesign application 2: Acceleration of system-level simulation by HW emulation

Winter-Spring 2001Codesign of Embedded Systems21 Emulation and prototyping systems (cont’d) Codesign application 3: Computer-aided prototyping Validate HW before manufacturing to avoid expensive redesign Prototyping of complex digital systems (HW + SW)

Winter-Spring 2001Codesign of Embedded Systems22 What we learned today Categorized digital systems This helps in decision-makings in codesign strategies and algorithms Reviewed problem areas within each application domain

Winter-Spring 2001Codesign of Embedded Systems23 Complementary notes Verilog Short Course Instructor: Farshid Soheili, Emad Semicon. Co. First session Saturday: Esfand 6th “Avecina-16” room VHDL short course will also be held soon

Winter-Spring 2001Codesign of Embedded Systems24 Complementary notes (cont’d) Optional paper presentation Any subtopic from second topic of today programme: System-Level Co-Design Issues