BEH30802 :: REAL-TIME EMBEDDED SYSTEM Mr. Mohamad Fauzi bin Zakaria Head of Mechatronic Lab. (formerly known as Control Technology Lab.) BLOCK Q 018-4640050 mfauzi@uthm.edu.my 1.0 introduction

Outline Embedded System Real-time Systems RTES in Mechatronics Application

Embedded Systems [www.webopedia.com]: An embedded system is “a specialized computer system that is part of a larger system or machine. Typically, an embedded system is housed on a single microprocessor board with the programs stored in ROM. Virtually all appliances that have digital interfaces (e.g., watches, microwaves, VCRs, cars) utilize embedded systems […]” Many embedded systems are real-time systems

Embedded System A device that has a programmable, special-purpose computer Interacts with the real world through sensing and/or actuation Have close interactions with the physical world Have constrained resources Power Memory OS and other software usually tailored to hardware Have real-time requirements Many embedded systems

The Challenges of Embedded SYSTEM Embedded computing systems are everywhere Billions of units produced yearly, versus millions of desktop units Its challenges High performance Low cost Low power Real-time deadlines Memory footprint Time-to-market

Current trend of Embedded system Please name the embedded system that you know… How to select embedded system? CPU Speed? Memory? Peripheral – USART/SPI, USB, ADC, DAC, EEPROM, direct memory access (DMA), digital camera interface (DCMI) etc. Footprint Power consumption – Operating voltage

Real-time Systems A real-time system is a system whose specification includes both logical and temporal correctness requirements. Logical Correctness: Produces correct outputs. Temporal Correctness: Produces outputs at the right time. In this course, we spend much time on techniques and technologies for achieving and checking temporal correctness.

Typical Characteristics of Real-Time Systems Event-driven, reactive. High cost of failure. Concurrency/multiprogramming. Stand-alone/continuous operation. Reliability/fault-tolerance requirements. Predictable behavior.

Example: Real-Time Applications Many real-time systems are control systems Example 1: A simple one-sensor, one-actuator control system

Simple Control System (Continued) Pseudo-code for this system: T is called sampling period. T is a key design choice. Typical range for T: seconds to milliseconds.

Time

Air Traffic Control (ATC)

Signal-Processing System Signal-processing systems transform data from one form to another. Examples: Digital filtering. Video and voice compression/decompression. Radar signal processing. Response times range from a few milliseconds to a few seconds.

TYPE of Real-Time System (RTS) 1. Hard RTS Failure to meet even a signle deadline may lead to complete or catastrophic system filure 2. Soft RTS Performance is degraded but not destroyed by failure to meet response-time constraint 3. Firm RTS few missed deadlines will not lead to total failure, but missing more than a few may lead to complete or catastrophic system failure.

HARD RTS Example: Air Traffic Control: a service provided by ground-based controllers who direct aircraft on the ground and through controlled airspace, and can provide advisory services to aircraft in non-controlled airspace. The primary purpose of ATC worldwide is to prevent collisions, organize and expedite the flow of traffic, and provide information and other support for pilots. Car Engine Management Control Anti-lock Braking System Pacemaker: a small device that's placed in the chest or abdomen to help control abnormal heart rhythms. This device uses electrical pulses to prompt the heart to beat at a normal rate. Fire Alarm System

Soft RTS Example Streaming audio-video (Youtube, stream broadcast etc) Webpage Automatic Washing machine Air-conditioning

FIRM RTS Example Music Sound System in the computer Video Conferencing (Skype, hangout etc.)

Self ACTIVITY Find three examples of hard, soft and firm real-time embedded system in 1. Automotive 2. Home Appliances 3. Industrial Automation 4. Home Automation 5. Medical System