Posted on May 06, 2016 at 22:49I have been trying to implement the Tickless Idle feature in FreeRTOS (which comes pre-implemented for STM32 processors).
In my main code I have turned off all IP except the pushbutton (EXTI0), which I want to use to wake the device. I call HAL_DBGMCU_DisableDBGSleepMode so the debugger will not interrupt sleeping. Then I suspend all tasks, this forces FreeRTOS's tickless idle to kick in.
I have modified PreSleepProcessing (which is called immediately before the WFI call) with code to record how long I am sleeping, and PostSleepProcessing to do nothing but hit any programmed breakpoint.
I hit the debug breakpoint in PreSleepProcessing (meaning it is prepared to go to sleep), and hit RUN, but the current does not drop. If I put a breakpoint in PostSleepProcessing it seems to hit immediately, but from the PreSleepProcessing breakpoint I know it is only sleeping for 209 ms.
I have breakpoints in all interrupts (including the RTOS ones) so I know none of those are causing it to wake. While awake (between PostSleepProcessing and PreSleepProcessing) the SysTick does run.
How do I know it's actually sleeping? I've been looking for a register that will indicate why it woke, the only one I can find is
PWR_SR1
, but that's for events and FreeRTOS is using WFI.
Should I be posting in the FreeRTOS forum?
Any help appreciated!
-Matt
#sleeping #freertos
