FreeRTOS
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FreeRTOS notes
operating system used and recommended by Neil M.
2017-12-08
Contents
Overview
Ted starting a wiki page to hold notes and findings from working through demos and tutorials on FreeRTOS operating system. First goals include:
- Learning what target CPUs, dev boards and systems run FreeRTOS
- Learning what emulators run and support testing of FreeRTOS instances
^ First Topics Explored
RTOS fundamentals covered in pages of FreeRTOS site:
These initial links will likely be moved or removed, they're just first places Ted checked out at FreeRTOS site:
- 2017-12-27 WED -
FreeRTOS demo applications described in overview fashion at https://www.freertos.org/a00102.html.
- https://www.freertos.org/a00017.html . . . source code organization,
- https://www.freertos.org/a00090.html . . . FreeRTOS ports, each its own web page,
- 2018-05-11 FRI - Quick-start page and configAssert():
^ FreeRTOS Ported To Microcontroller Families
- 2017-12-15 FRI -
FreeRTOS ports to various microcontroller families:
- https://www.freertos.org/a00090.html
- https://www.freertos.org/FreeRTOS-for-Cortex-M0-LPC1114-LPCXpresso.html NXP LPC1114 ARM Cortex-M0 Demo
- https://www.freertos.org/FreeRTOS-for-STM32F4xx-Cortex-M4F-IAR.html
^ Specific Boards Usable with FreeRTOS
2018-04-10
Singleton Pattern mentioned in section named "Basics" in the following wiki document about San Jose State University LPC1758 dev board:
- https://www.freertos.org/FreeRTOS_Support_Forum_Archive/April_2010/freertos_STM32F10X-128k-Eval_freeRTOS_V6.0.4_OK_3669009.html
- https://github.com/atgreen/FreeRTOS/tree/master/Demo/CORTEX_STM32F100_Atollic
# # # Trouble-shooting Related Notes Follow # # #
^ FreeRTOS Architecture
Context switchting, how context switched between tasks in FreeRTOS . . .
Task Control Block (TCB) memory allocation . . .
Task priorities assignable defined in tasks.h:
~/Downloads/freertos/FreeRTOSv10.0.1/FreeRTOS/Source$ grep -nr tskIDLE_PRIORITY ./* ./include/task.h:154:#define tskIDLE_PRIORITY ( ( UBaseType_t ) 0U ) ./include/task.h:307: xTaskCreate( vTaskCode, "NAME", STACK_SIZE, &ucParameterToPass, tskIDLE_PRIORITY, &xHandle ); ./include/task.h:423: tskIDLE_PRIORITY,// Priority at which the task is created. ./include/task.h:688: xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle ); ./include/task.h:856: xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle ); ./include/task.h:861: // It was created with tskIDLE_PRIORITY, but may have changed ./include/task.h:863: if( uxTaskPriorityGet( xHandle ) != tskIDLE_PRIORITY ) ./include/task.h:988: xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle ); ./include/task.h:993: vTaskPrioritySet( xHandle, tskIDLE_PRIORITY + 1 ); ./include/task.h:998: vTaskPrioritySet( NULL, tskIDLE_PRIORITY + 1 ); ./include/task.h:1030: xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle ); ./include/task.h:1079: xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle ); ./include/task.h:1154: xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, NULL ); ./include/task.h:1208: xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, NULL ); ./queue.c:2031: uxHighestPriorityOfWaitingTasks = tskIDLE_PRIORITY;
^ Task Control Block - TCB
Exploring the Task Control Block and stack implementations of FreeRTOS. Following forum post mentions stack checking as a feature of FreeRTOS 7.1 which can be enabled. This post also mentions interrupt priorities which range from 1 to 15:
^ Memory Management and Heap
^ Software Timers
Useful forum post regarding xTaskGetTickCount(): 2020-07-20
^ References
- https://www.freertos.org/History.txt . . . change history in text format gives a list of FreeRTOS stable releases
- https://www.freertos.org/a00104.html . . . source code download instructions
2018-06-08 - Friday
