Embedded Systems Design ICT 5307

Embedded System What is an embedded System??? Any IDEA???

Embedded System Dedicated to a specific task Dedicated user interface Includes limited resources Efficient ◦Energy, Code-size, Run-time, Weight, Cost Dependable ◦Reliability, Availability, Safety, Security May have to operate in extreme environmental condition (high temp, humidity)

Embedded System May has to meet real-time constraint ◦A real-time system must react to stimuli from the controlled object (or the operator) within the time interval dictated by the environment. ◦For real-time systems, right answers arriving too late are wrong ◦A guaranteed system response has to be explained without statistical arguments. Frequently connected to physical environment through sensors and actuators Hybrid systems (analog + digital parts) May be distributed

Application Areas Computer Appliances Office automation Industrial Automation Medical Electronics Computer Networking Telecommunications Wireless Technologies Instrumentation Security

Embedded System Replacement for discrete logic-based circuits Provide functional upgrades Provide easy maintenance upgrades Improves mechanical performance Protection of intellectual property Replacement for analogue circuits

Analog Signal Processing

Digital Signal Processing

Analogue signals have infinite values between Their working range range. Digital signal processors represents the infinite variations with a finite number of steps / values Low pass filter roll-off ◦16 bit word length => 90 dB ◦24 bit word length => 120 dB

Embedded System Processor Memory Peripherals ◦Binary outputs ◦Serial outputs ◦Analogue values ◦Displays ◦Time derived outputs Software

Embedded System Software ◦Initialization and configuration ◦Operating system or run-time environment ◦The applications software itself ◦Error handling ◦Debug and maintenance support. Algorithms

Motorola MC68HC705C4A

Data Processors The larger data size was needed to help support higher precision arithmetic The increased address space was needed to support bigger blocks of memory for larger programs The complex instruction was needed to help reduce the amount of memory required to store the program

Data Processors Pipelining Instruction ◦Instruction fetching ◦Decoding ◦Execution Pipelining stalls ◦Branching

Data Processors

Intel Pentium

Reduced instruction set computing (RISC) The 80/20 rule All instructions will be executed in a single cycle (sometimes multiple cycles may be needed) Memory will only be accessed via load and store instructions All execution units will be hardwired with no microcoding

The Berkeley RISC model

Sun SPARC RISC processor

The ARM RISC architecture Currently 50+ manufacterers Standard RISC architecture techniques ◦Load-store architecture ◦Simple addressing modes based on register contents and instruction information ◦fixed length instructions (4 byte word) Register banking Special registers: ◦Register 14: Link register ◦Register 15: Program counter ◦Register 13: Stack pointer

The ARM processing modes

Digital Signal Processors Example: ◦FIR filter ◦Sampled data ◦Coefficients ◦Multiplication and addition

Motorola DSP56000

Marks Distribution Mid 1 – 5 th / 6 th week – 30% Mid 2 – 9 th / 10 th week - 30% Final – After 14 th week – 40%

Processor Selection