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Original question:

MSP430F6779A: Can PMM26 occur even setting the reset pin to NMI?

MSP430F6779A: What is proper process to do System Non-maskable Interrupt Service Routine?

TinK
Intellectual 745 points
Part Number: MSP430F6779A

as we have setting the reset pin to NMI for prevent PMM26

int _system_pre_init(void)
{
/* Insert your low-level initializations here */
__disable_interrupt();
WDTCTL = WDTPW+WDTHOLD;

// Clear RTCHOLD Bit after reset
RTCCTL0_H = RTCKEY_H; // unlock
RTCCTL1 &= ~RTCHOLD; // release RTC
RTCCTL0_H = 0x00; // lock

SFRRPCR = SYSNMI | SYSNMIIES | SYSRSTRE;

/* Return value:
* 1 - Perform data segment initialization.
* 0 - Skip data segment initialization.
*/
return 1;
}

What is proper process to do System Non-maskable Interrupt Service Routine?

Can it be blank as below?

//------------------------------------------------------------------------------
//                         Interrupt Service Routine
//------------------------------------------------------------------------------
#pragma vector=SYSNMI_VECTOR            /* 0xFFFC System Non-maskable */
__interrupt void int_SYSNMI(void)
{

}

  • 0
    TI__Mastermind 28070 points

    Hi TinK,

    You will also want to set NMIIE in the SFRIE1 register. 

    I also believe the external NMIIFG is a User NMI, so your vector should be UNMI_VECTOR. At a minimum I would read the SYSUNIV register to clear the NMIIFG in each ISR. 

    Best Regards,
    Brandon Fisher

  • 0 in reply to Brandon Fisher94
    Intellectual 745 points

    Hi Brandon Fisher,

    Thank you for information.

    If the NMIIE is clear (disable).

        SFRIE1 &= ~(NMIIE);            // SFRIE1    �? NMI Interrupt      Disable(b4)

    What processes are required in User NMI interrupt service routine in case NMIIE  is clear?

  • 0 in reply to TinK
    TI__Mastermind 28070 points

    Hi TinK,

    Your USER_NMI could look something like this: 

    // UNMI Interrupt Service Routine
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=UNMI_VECTOR
__interrupt void UNMI_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(UNMI_VECTOR))) UNMI_ISR (void)
#else
#error Compiler not supported!
#endif
{
    switch(__even_in_range(SYSUNIV, SYSUNIV_AUXSWGIFG))
    {
        case SYSUNIV_NONE: break; // No interrupt Pending
        case SYSUNIV_NMIIFG:
            //Trigger POR
            PMMCTL0 = PMMPW | PMMSWPOR;
            break; // NMIIFG
        case SYSUNIV_OFIFG: break; // OFIFG
        case SYSUNIV_ACCVIFG: break; // ACCVIFG
        case SYSUNIV_AUXSWGIFG: // BUSIFG
            break;
        default: 
            break;
    }
}

    On NMIIFG it should trigger a POR.

    Best Regards,
    Brandon Fisher

  • 0 in reply to Brandon Fisher94
    Intellectual 745 points

    Hi Brandon Fisher,

    Are there any problems if no process in USER_NMI in my present source that the NMIIE is disable?

    SFRIE1 &= ~(NMIIE); // SFRIE1

  • +1 in reply to TinK
    TI__Mastermind 28070 points

    IF NMIEE is disabled I expect you will never trigger the UNMI ISR. In that case it wont matter what you have inside the handler.

    Best regards,
    Brandon Fisher

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