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Problem passing variable to function in ISR

Jeremy Brookley

So, I have a problem sending a value to a function at different parts of my code. Here is my code:

void LongRightShift(unsigned char NumBitsShift)
{
// My Code Here
     NumBitsShift = NumBitsShift; // So you can place a breakpoint here and read NumBitsShift
}

Now, when I call

LongRightShift(2);

in the main part of my program, NumBitsShift = 2. When I call it in the Decimator2_ISR, NumBitsShift = 1;

Does this have to do with the way I'm passing it or is there a conflict with running other functions in an ISR?

Any help you can give me would be appreciated. Thanks!

Parents
  • 0 in reply to Jeremy Brookley 

    void AverageOutput(void)
{
        unsigned char tempvar = 0;
        unsigned char NumOutSamples = 0;
        unsigned char Pressure1 = 500;

        if(Pressure1<600)
        {
                NumOutSamples = 0;
                AveragedPressureOut=Pressure1;
        }
        else
        {
                //More code here
        }
        tempvar+=1; // Place breakpoint on this line
}


    That code does nothing, the Optimizer can remove it since it will not change the operation of the code.
    If tempvar was static it may keep it. it is was a volatile and declared out side the function it would be forced to keep it.

Reply
  • 0 in reply to Jeremy Brookley 

    void AverageOutput(void)
{
        unsigned char tempvar = 0;
        unsigned char NumOutSamples = 0;
        unsigned char Pressure1 = 500;

        if(Pressure1<600)
        {
                NumOutSamples = 0;
                AveragedPressureOut=Pressure1;
        }
        else
        {
                //More code here
        }
        tempvar+=1; // Place breakpoint on this line
}


    That code does nothing, the Optimizer can remove it since it will not change the operation of the code.
    If tempvar was static it may keep it. it is was a volatile and declared out side the function it would be forced to keep it.

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