CMSIS RTOS Variable Problem

[kasun_duminda92]

Posted on July 02, 2013 at 17:56

This discussion was mistakenly add in this section. It should be in the STM32 Discovery section. So it was moved there.

#discovery #stm32 #rtos #cmsis

[dthedens23]

Posted on July 02, 2013 at 20:18

I cannot say why it is hanging.  perhaps your stack size is way to small?

osThreadDef(Funct, osPriorityNormal, 1, 256);

Waking a thread every 1ms is pretty harsh.  Try every 50ms and increment count by 50.

I can say that you have two threads nakedly accessing the same variable.  That access is not thread safe,

First, the variable should use the keyword ''volatile''

second, there should be a mutex that each thread calls to gain access to the variable.  Only one thread at a time can ''hold'' the variable, to read or modify and then, the thread releases the mutex.

NOTE: in this simple example it might not matter to much, since one thread is the consumer and the other thread is the provider.  But naked access will cause problems.

[Amel NASRI]

Posted on July 30, 2013 at 10:40

Details in STM32 Discovery forum:

https://my.st.com/public/STe2ecommunities/mcu/Lists/STM32Discovery/Flat.aspx?RootFolder=https://my.st.com/public/STe2ecommunities/mcu/Lists/STM32Discovery/CMSIS%20RTOS%20Problem&FolderCTID=0x01200200770978C69A1141439FE559EB459D75800084C20D8867EAD444A5987D47BE638E0F&currentviews=30

.

Replies should be given there.

-Mayla-