FreeRTOS

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FreeRTOS notes
operating system used and recommended by Neil M.
2017-12-08

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:

• https://www.freertos.org/implementation/a00002.html

These initial links will likely be moved or removed, they're just first places Ted checked out at FreeRTOS site:

• https://www.freertos.org/rtos-trace-macros.html
• https://freertos.org/a00110.html#configASSERT

- 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,

^ FreeRTOS Ported To Microcontroller Families

- 2017-12-15 FRI -

FreeRTOS ports to various microcontroller families:

• https://www.freertos.org/a00090.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:

• http://socialledge.com/sjsu/index.php/SJ_One_Board
  • http://socialledge.com/sjsu/index.php/Main_Page
  • http://socialledge.com/sjsu/images/d/de/2012SJOneBoardSchematic.pdf

# # # Trouble-shooting Related Notes Follow # # #

^ FreeRTOS Architecture

Task Control Block (TCB) memory allocation . . .

• https://www.freertos.org/FreeRTOS_Support_Forum_Archive/January_2018/freertos_Task_control_block_memory_allocation_55c3c1a5j.html

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:

• https://www.freertos.org/FreeRTOS_Support_Forum_Archive/December_2012/freertos_pxCurrentTCB_corrupted_6477695.html

^ 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

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