CS452 - Real-Time Programming - Spring 2008

Lecture 5 - Kernel


Questions & Comments

  1. Link register
  2. Lab should be ready Friday: Assignment 2 (aka 1)

Devices

Real-time clock

Usually a count-down timer

Programming

Reading

USART

Universal Synchronous/Asynchronous Receiver/Transmitter

We load a piece of data, usually a byte. It shifts out the bits on a time-multiplexed signal

Programming

Using


Kernel of a Real-time Operating System

Diagram

What Does the Kernel Provide

Tasks

Communication

Communication has two sides

  1. sharing information
  2. handshaking

We use Send/Receive/Reply (SRR) to do both.

  1. Send blocks
  2. Receive blocks: is synchronous with the call to send
  3. Reply doesn't block: is synchronous with the return from send

Diagram

Synchronization

  1. Between tasks
  2. With internal events
  3. With external events


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