FreeRTOS英文使用教程

www.FreeRTOS.org This document was supplied to jmclurkin@rice.edu
 
 
 
Contents
 
List of Figures vi
 
List of Code Listings viii
 
List of Tables xi
 
List of Notation xii
 
Preface FreeRTOS and the Cortex-M3 1
 
Multitasking on a Cortex-M3 Microcontroller 2
 
An Introduction to Multitasking in Small Embedded Systems 2
 
A Note About Terminology 2
 
Why Use a Real-time Kernel? 3
 
The Cortex-M3 Port of FreeRTOS 4
 
Resources Used By FreeRTOS 5
 
The FreeRTOS, OpenRTOS, and SafeRTOS Family 6
 
Using the Examples that Accompany this Book 8
 
Required Tools and Hardware 8
 
Chapter 1 Task Management 9
 
1.1 Chapter Introduction and Scope 10
 
Scope 10
 
1.2 Task Functions 11
 
1.3 Top Level Task States 12
 
1.4 Creating Tasks 13
 
The xTaskCreate() API Function 13
 
Example 1. Creating tasks 16
 
Example 2. Using the task parameter 19
 
1.5 Task Priorities 22
 
Example 3. Experimenting with priorities 23
 
1.6 Expanding the ‘Not Running’ State 26
 
The Blocked State 26
 
The Suspended State 27
 
The Ready State 27
 
Completing the State Transition Diagram 27
 
Example 4. Using the Blocked state to create a delay 28
 
The vTaskDelayUntil() API Function 31
 
Example 5. Converting the example tasks to use vTaskDelayUntil() 33
 
Example 6. Combining blocking and non-blocking tasks 34
 
1.7 The Idle Task and the Idle Task Hook 37
 
Idle Task Hook Functions 37
 
Limitations on the Implementation of Idle Task Hook Functions 38