Micrium OS -III Timer callback function not getting called

Question

I am using keil compiler for arm(stm32F4). In my code I have created a timer to call a function which calls a function from a *.lib file.

The function is getting called if I am using linker optimization level-0 (O-0) and the application works fine. If I am changing optimization level to (O-1), the function is not getting included in executable.

I checked the timer structure in watch window and the counter values are being updated and the callback function address is present which matches the address in map file.

From the keil help I got to know that in Level 1-o1 optimization the following optimizations are done.

• Breakpoints may not be set on dead code.
• Values of variables may not be available within their scope after
  they have been initialized. For example if their assigned location
  has been reused.
• Functions with no side-effects may be called out of sequence, or may be omitted if the result is not needed.

I tried calling the lib function from a task. But still the same thing is happening. As the function was directly referenced , I suspect the compiler thinks that the function is having no-side effects.

How can I resolve this?

void LCDVsync_TMRHandler(void *ptmr, void *parg)
{
    OS_ERR err;
    OSWrappers::signalVSync();

}

void LCDFrontPorch_TMRHandler(void *ptmr,void *arg)
{
     OS_ERR err;
     HAL::getInstance()->frontPorchEntered();
     OSTmrStart(&ostmr_LCDVsync,&err);

}

Code which creates the timer.

OSTmrCreate(&ostmr_LCDVsync,"LCD vsync signalling",10,0,OS_OPT_TMR_ONE_SHOT,LCDVsync_TMRHandler,(void *)0,&err);
if(OS_ERR_NONE != err)
{
    DEBUG_ERROR_APP("ERROR: APP.C : AppTmrCreate : LCD vsync signalling tmr create failure");
}
OSTmrCreate(&ostmr_LCDFrontPorch,"LCD Front porch",0,20,OS_OPT_TMR_PERIODIC,LCDFrontPorch_TMRHandler,(void *)0,&err);
if(OS_ERR_NONE != err)
{
    DEBUG_ERROR_APP("ERROR: APP.C : AppTmrCreate : LCD vsync signalling tmr create failure");
}

Code which is starting the periodic timer.

OSTmrStart(&ostmr_LCDFrontPorch,&err);

Compiler control string.

c --cpu Cortex-M4.fp -g -O0 --apcs=interwork -I..\platform\3rd_Party_ST\Drivers\CMSIS\Include 
-I C:\Users\bro\Desktop\Project\Charger\Workspace\some\yeah\RTE 
-I C:\Keil_v5\ARM\PACK\Keil\STM32F4xx_DFP\2.5.0 
-I C:\Keil_v5\ARM\CMSIS\Include 
-I    C:\Keil_v5\ARM\PACK\Keil\STM32F4xx_DFP\2.5.0\Drivers\CMSIS\Device\ST\STM32F4xx\Include 
-D__UVISION_VERSION="513" -DSTM32F429xx -DUSE_HAL_DRIVER -DSTM32F429xx -DUSE_STM324x9I_EVAL -DUSE_I2C1 -DUSE_SPIX -DUSE_USB_FS -DUSECB_SDOREQ -o ".\Objects\*.o" --omf_browse ".\Objects\*.crf" --depend ".\Objects\*.d" 

Answer 1

Since it works without optimization, I would suggest tricking the compiler while optimization is turned on. Specifically, you can do something like this:

if ( funcReturnsFalse() )
{
    CallBackFcn( param1, param2 );   //  Whatever your real callback is
}

You don't want to actually make the call, because that changes the logic you have working while optimization is off. And the compiler is likely smart enough to understand something like if ( false ) ..., so having a function call ( funcReturnsFalse() ) is probably enough for the compiler to believe you will be using CallBackFcn().

I have run into this problem before (not with Micrium), and this technique worked for me.