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[FreeRTOS Home] [Live FreeRTOS Forum] [FAQ] [Archive Top] [April 2017 Threads] Free RTOS - strange behavior on Cortex-M3.Posted by ravikiranhv on April 26, 2017 Hello experts,
I am working on freeRTOS V9.0 on Cortex M3. I have two application threads and 2 interrupts. Both the threads blocks on event which are posted by interrupts (I am using API ending with ISR from interrupts). Evevryting works fine if I have multiple thread and a single interrupt.
Have multiple randomobservation on my setup on each boot.
Case-1: System hangs after starting RTOS. Both threads and Interrupts not working
Case-2: Threads are not running but both the interrupts working !
Case-3: Threasds start running automatically after some time (about 60 seconds) after 10/20 interrupt processing
Case-4: Everything works fine without any problem
I understood freeRTOS configuration requirement for interrupts from here and everything looks fine !
http://www.freertos.org/FAQHelp.html
http://www.freertos.org/a00110.html#kernel_priority
Appreciate your bvaluable feedback :)
Thanks
Free RTOS - strange behavior on Cortex-M3.Posted by edwards3 on April 26, 2017 Do you have configASSERT() defined?
Which M3 are you using and what is configMAXSYSCALLINTERRUPT_PRIORITY set to?
Free RTOS - strange behavior on Cortex-M3.Posted by ravikiranhv on April 27, 2017 Yes configASSERT() is defined. Our Cortex M3 implements 3 bits(MSB) for priority
configMAXSYSCALLINTERRUPTPRIORITY (191) //(i.e. priority 5).
configKERNELINTERRUPT_PRIORITY (240)
Both ISR's calling free RTOS API's are set to priority 240.
Please suggets if I am missing anything.
Thanks in advance
Free RTOS - strange behavior on Cortex-M3.Posted by rtel on April 27, 2017 240 is actually using 4 bits, but that shouldn't matter because the
unimplemented bit will be ignored anyway.
Can you please say which chip you are using - if it is an STM32 then you
also have to explicitly tell it not to sub-divide the priorities. Are
you 100% sure it has three priority bits defined? We have had incidents
where documentation on this has been wrong, which is why the head
revision Cortex-M code in SVN has additional asserts() to actually
measure this to determine if the configuration file settings are correct.
Free RTOS - strange behavior on Cortex-M3.Posted by ravikiranhv on April 29, 2017 Hi,
Thanks for the inputs.
I am using Max32550 controller from Maxim with 3 bit priority implementation.
Please suggest how to go about.
Appreciate your help
Free RTOS - strange behavior on Cortex-M3.Posted by rtel on April 30, 2017 Try setting configKERNELINTERRUPTPRIORITY to 224, and if that does not
help, update to the latest version of port.c, which contains more
configASSERT() statements. Link assumes GCC, and the new asserts assume
either _NVICPRIOBITS or configPRIOBITS is set to 3 in
FreeRTOSConfig.h:
https://sourceforge.net/p/freertos/code/HEAD/tree/trunk/FreeRTOS/Source/portable/GCC/ARM_CM3/
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