CS244 Introduction to Embedded Systems and Ubiquitous Computing Instructor Eli Bozorgzadeh Computer Science Department UC Irvine Winter 2010 Introduction to Embedded Systems Suggested Textbooks Embedded System Design by F Vahid and Givargis Wiley 2002 Embedded System Design by P Marwedel Kluwer Academic 2003 Embedded System Design by Gajski Abdi and et al Springer 2008 Other sources Lecture notes handouts Winter 2010 CS 244 2 Course outline Lectures Tue Thu 9 30 11 00 a m DBH 130 Office hours email me first to make sure I am available Grading policy 25 homework 25 Paper presentation Each of you presents a paper assigned to you assignment around week 4 and presentation around week 8 9 30 embedded system Example project week 6 10 20 Exam late midterm week 8 9 Winter 2010 CS 244 3 Outline What are embedded systems Embedded System Components Hardware software Embedded System applications Model languages and tools Hardware software co design and synthesis Reconfigurable Computing Real time Operating systems Copyrighted Material adapted from slides by Peter Marwedel Frank Vahid Tony Givargis Dan Gajski andWinter Nikil 2010Dutt CS 244 4 What s an Embedded Embedded systems System information processing systems embedded into a larger product Two types of computing Non Embedded Systems Desktop produced millions year Embedded billions year PCs servers and notebooks The future of computing Automobiles entertainment communication aviation handheld devices military and medical equipments Winter 2010 CS 244 5 Embedded Systems Devices other than desktop PCs servers and notebooks Electricity running through Perform something intelligent Hardware software which form a component of a larger system but are concealed from user Computers camouflaged as non computers The future of computing Winter 2010 CS 244 6 6 An Example Embedded System Digital Camera Block Diagram Winter 2010 CS 244 7 ES Simplified Block Diagram actuators Winter 2010 CS 244 8 Course Outline Hardware Components Concept Specification Hardware HW SW Partitioning Estimation Exploration gn i s De t u ayo L sis e n th y S De sig n C om pil ati on Software Software Components Winter 2010 CS 244 Validation and Evaluation area power performance 9 Components of Embedded Systems Analog Components Digital Components Sensors Actuators Controllers Processor Coprocessors Memories Controllers Buses Application Specific Integrated Circuits ASIC Converters A2D D2A Software Application Programs Exception Handlers Winter 2010 CS 244 Hardware Software 10 Hardware Components Hardware Components of Embedded Systems an example Memory Controllers Interface Software Application Programs Coprocessors Processor ASIC Converters Analog Winter 2010 CS 244 Digital 12 Analog Processors What is a processor General purpose GP processors Artifact that computes runs algorithms Controller and data path Variety of computation tasks Functional flexibility and low cost at high volumes maybe Slow and power hungry Single purpose SP processors or ASIC One particular computation task Fast and power efficient Functional inflexibility and high cost at low volumes maybe Winter 2010 CS 244 13 13 GP SP Processor Architecture Status Data Input Data Path Data Output Controller Control Control Winter 2010 CS 244 14 14 General purpose processors Programmable device used in a variety of applications Features Program memory General datapath with large register file and general ALU User benefits Also known as microprocessor Low time to market and NRE costs High flexibility Examples Controller Datapath Control logic and State register Register file IR PC Program memory General ALU Data memory Assembly code for total 0 for i 1 to Pentium Athlon PowerPC Winter 2010 CS 244 15 Application specific IS processors ASIPs Programmable processor optimized for a particular class of applications having common characteristics Compromise between general purpose and ASIC custom hardware Features Program memory Optimized datapath Special functional units Benefits Some flexibility good performance size and power Examples DSPs Video Signal Processors Network Processors Winter 2010 CS 244 Controller Datapath Control logic and State register Registers IR PC Program memory Custom ALU Data memory Assembly code for total 0 for i 1 to 16 Application Specific ICs ASICs Digital circuit designed to execute exactly one program Features coprocessor hardware accelerator Contains only the components needed to execute a single program No program memory Controller Datapath Control logic index total State register Data memory Benefits Fast Low power Small size Winter 2010 CS 244 17 Application Specific Circuits Custom designed ASIC circuits necessary if ultimate speed or energy efficiency is the goal and large numbers can be sold Approach suffers from long design times and high costs Winter 2010 CS 244 18 GP vs SP Processors GP Programmable controller Control logic is stored in memory Fetch decode overhead Highly general data path ASIC Typical bit width 8 16 32 64 Complete set of arithmetic logic units Large set of registers High NRE sale volume Hardwired controller Highly tuned data path No need for program memory and cache No fetch decode overhead Custom bit width Custom arithmetic logic units Custom set of registers Low NRE sale volume Winter 2010 CS 244 19 19 Storage What is a memory Write ability ability of memory to hold stored bits after they are written Many different types of memories Manner and speed a memory can be written Storage permanence Artifact that stores bits Storage fabric and access logic Flash SRAM DRAM etc Common to compose memories Winter 2010 CS 244 20 20 Write ability Ranges of write ability High end Middle range Processor writes to memory but slower E g FLASH EEPROM Lower range Processor writes to memory simply and quickly E g RAM Special equipment programmer must be used to write to memory E g EPROM OTP ROM Low end Bits stored only during fabrication E g Mask programmed ROM Winter 2010 CS 244 21 21 Storage permanence Range of storage permanence High end Middle range Holds bits days months years after memory s power source turned off E g NVRAM Lower range Essentially never loses bits E g mask programmed ROM Holds bits as long as power supplied to memory E g SRAM Low end Begins to lose bits almost immediately after written E g DRAM Winter 2010 CS 244 22 22 Storage permanence Memory Types Mask programmed ROM In system programmable Ideal OTP ROM EPROM EEPROM Flash NVRAM Nonvolatile SRAM DRAM