1. BEH30802 :: REAL-TIME EMBEDDED SYSTEM
Mr. Mohamad Fauzi bin Zakaria
Head of Mechatronic Lab.
(formerly known as Control Technology Lab.)
BLOCK Q
1.0 introduction

2. Outline Embedded System Real-time Systems
RTES in Mechatronics Application

3. 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

4. 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

5. 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

6. 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

7. 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.

8. 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.

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

10. 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.

11. Time

12. Air Traffic Control (ATC)

13. 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.

14. 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.

15. 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

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

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

18. 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