CS244 Introduction to Embedded Systems and Ubiquitous Computing Instructor Eli Bozorgzadeh Computer Science Department UC Irvine Winter 2012 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 Mon Wed Fri 3 00 3 50 p m Office hours Friday 10 11 a m Grading policy 25 reading assignments quizzes 2 3 25 homework and project assignments 2 3 25 literature survey group of 2 3 25 Final 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 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 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 6 6 An Example Embedded System Digital Camera Block Diagram 7 ES Simplified Block Diagram actuators 8 Course Outline Hardware Components Concept Specification Hardware HW SW Partitioning Estimation Exploration Software Components gn i s De t u ayo L sis e n th y S De sig n C om pil ati on Software 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 Hardware Software 10 Hardware Components Hardware Components of Embedded Systems an example Memory Controllers Interface Software Application Programs Coprocessors Processor ASIC Converters Analog 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 13 13 GP SP Processor Architecture Status Data Input Data Path Data Output Controller Control Control 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 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 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 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 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 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 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 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 22 22 Storage permanence Memory Types Mask programmed ROM In system programmable Ideal OTP ROM EPROM EEPROM Flash NVRAM Nonvolatile SRAM DRAM Write ability 23 23 Communication What is a bus An artifact that transfers bits Wires air or fiber and interface logic Associated with a bus we have Connectivity scheme Protocol Serial Communication Parallel Communication Wireless Communication Ports Timing Diagrams Read and write cycles Arbitration scheme error detection correction DMA etc 24 24 Serial Communication A single wire used for data transfer One or more additional wires used for control but some protocols may