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MSP432P401R: NOCP: Attempt to use co processor Instruction CSFR: FaultISR

Krishn_JI
Expert 2135 points

Part Number: MSP432P401R

As shown in the picture my code jumps to FaultISR every time From one instruction and that instruction is

if (i < j)
{
     tx = ArrayA[i];             // and that line is this from which it evry time jumps to FaultISR.
     ArrayA[i] = ArrayA[j];
     ArrayA[j] = tx;
         	
}

 after shifting to FaultISR these bits are set as shown in figure... How to solve this problem.

  • 0
    Expert 2135 points

    Photograph given shows CP10 bit which is also set at FaultISR which shows 

    unprivileged access generates a
    NOCP UsageFault.

  • 0 in reply to Krishn_JI
    Guru 96315 points

    My first guess is that ArrayA is floating point, and the FPU isn't turned on. It's normally enabled in SystemInit (the source is in your project) as 0x00f00000, based on __FPU_USED. Check the project to see if -D__FPU_USED=1 is set. There's also a project setting (Build Settings->Compiler->Processor->Floating point) which may figure in here somewhere.

    I don't see CPACR in your screenshot. If it's really set to 0x00100000, that's rather unusual, since the reset value is 0 [Ref DUI0553A Table 4-49] and SystemInit doesn't set it to that either.

    In any case, there's nothing wrong with your main() enabling the FPU explicitly (copied from system_msp432p401r.c): 

    >SCB->CPACR |= ((3UL << 10 * 2) | (3UL << 11 * 2)); // Enable FPU

    If ArrayA isn't floating point, my next guess is that you've misspelled an ISR name.

    [Edit: Fixed reference]

  • 0 in reply to Bruce McKenney
    Expert 2135 points

    Adding this line to clock routine just solved my problem.... thank you so much Bruce Mckenney47378   :)

    SCB->CPACR |= ((3UL << 10 * 2) | (3UL << 11 * 2)); // Enable FPU  

  • 0 in reply to Krishn_JI
    Guru 96315 points

    I'm glad it worked out. This is how we did it back in the Ancient Days. I think there's a mechanism that is supposed to do this auto-magically now, but I never had the patience to figure out how it worked.

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