Quality RTOS & Embedded Software

 Real time embedded FreeRTOS RSS feed 
Quick Start Supported MCUs PDF Books Trace Tools Ecosystem


List of tips on what to check when it hangs

Posted by Nobody/Anonymous on June 24, 2006
I am quite new to FreeRTOS and often find myself doing some changes to my code, only to find it doesnt work anymore.... recognise this? Especially if you change more than just a few lines of code....

So, heres my personal check-list when that happens. Please post also your tips here!

Crash solving for FreeRTOS, AT91SAM7A3-EK and IAR EWARM:

* try to reboot the Eval card

* no bounds check : added too much text to a string (than allocated)?

* no auto size heap: added too much vars for the task heap size?

* some task blocking long times, and locking itself?

* some task in a non-blocking wait, locking other lower tasks?

* vars in a function are only initialised once

* increase total heap size if added more tasks, queues, semaphores

* check task prios - someone locking the others?

* check irq levels - someone taking over?

* check rtos tick rate, runing too fast/slow?

* try reboot jtag

* try reboot iar ewarm

* constant meant to be float is defined without decimal point

* connected peripheral cant keep up (115200kbps serial port for example)

* queuSendFromIsr must always start with taskwoken=pdFALSE

* any ISR running too much/fast/wild? pwm... adc... dbgu/usart...

* check the A3 errata section in the datasheet

* could be a bug in an example file, in FreeRTOS or the A3 chip, check the web

RE: List of tips on what to check when it hangs

Posted by Nobody/Anonymous on June 24, 2006
one more...

* try running in non-debug mode

RE: List of tips on what to check when it hangs

Posted by Nobody/Anonymous on June 25, 2006
Some of these (variable initialization, etc) are C related rather than FreeRTOS but maybe some others could form part of a check list in the FAQ section?

RE: List of tips on what to check when it hangs

Posted by Nobody/Anonymous on June 25, 2006
Yes, that would be a good idea. Especially if we get more people contributing and someone really good at this sorting, selecting and explaining...

I do think its quite important to have the non RTOS stuff too.... The most common C errors and also HW related stuff like trying reboot the card, and compiler related like trying non-debug mode. Also to show that not everything is RTOS blame...;-) It could be divided into sections, like RTOS, C/Asm, Compiler/GUI, HW, Misc etc for a complete "FreeRTOS Developers checklist"....

What would be nice is an ordered list, listing the most common problems first (roughly), like rebooting the HW that I have to do all the time... but then the different sections fall...


1. Try rebot your HW (HW)

2. Higher prio task blocking (RTOS)

3. Variable initialization (C/Asm)

4. xxxx x x x x x x (HW: IAR + AT91)

5. .....


[ Back to the top ]    [ About FreeRTOS ]    [ Privacy ]    [ Sitemap ]    [ ]

Copyright (C) Amazon Web Services, Inc. or its affiliates. All rights reserved.

Latest News

NXP tweet showing LPC5500 (ARMv8-M Cortex-M33) running FreeRTOS.

Version 10.1.1 of the FreeRTOS kernel is available for immediate download. MIT licensed.

View a recording of the "OTA Update Security and Reliability" webinar, presented by TI and AWS.


FreeRTOS and other embedded software careers at AWS.

FreeRTOS Partners

ARM Connected RTOS partner for all ARM microcontroller cores

Espressif ESP32

IAR Partner

Microchip Premier RTOS Partner

RTOS partner of NXP for all NXP ARM microcontrollers


STMicro RTOS partner supporting ARM7, ARM Cortex-M3, ARM Cortex-M4 and ARM Cortex-M0

Texas Instruments MCU Developer Network RTOS partner for ARM and MSP430 microcontrollers

OpenRTOS and SafeRTOS

Xilinx Microblaze and Zynq partner