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CCS/TMS320F28075: "NaN" value for variable

Joe Zhu
Intellectual 2540 points
Part Number: TMS320F28075

Tool/software: Code Composer Studio

Hi Champion,

My customer find one of F28075 in address: 0x148C(CLA2CPURAM) will have NaN value, if they put one variable here. If they initialize it in Task 8, it will fix. So we want to why just this address in specific F28075 will report NaN value before initialize. What means NaN in CCS? Because this issue is happen in factory , so we should know its root cause.

Thanks 

BR

Joe

  • 0
    TI__Guru**** 466071 points

    Hi Joe,

    Joe Zhu said:
    So we want to why just this address in specific F28075 will report NaN value before initialize. What means NaN in CCS?

    NaN = Not a Number. Basically it is stands for a value that is undefined or not presentable, especially for floating point values.

    CLAfLKdcm is a float type and the value at that address is: 0xffd6a83d

    In binary, it is: 11111111110101101010100000111101

    NaN's are represented by a bit pattern with an exponent of all 1s and a non-zero fraction.

    Thanks

    ki

  • 0 in reply to Ki
    TI__Intellectual 2540 points

    Hi Ki,

    So you means if I am not initialize the variable, its value maybe NaN? Because we test more the 30 thousand F28075, just one in fix address wii be initialize to this value. Another question is what is the rate variable will be NaN?

    Thanks!
    BR

    Joe

  • 0 in reply to Joe Zhu
    TI__Guru**** 466071 points

    Joe - all I can tell you is why you see that variable evaluated to "NaN" by the debugger (as explained in my prior post). Why the memory address for that variable contains the value it does (0xffd6a83d), I cannot explain. But somehow that address is set to that value and you can try using the debugger to determine when and why.

    ki