CCS/MSP432P401R: Timer UP MODE

1) TA0CCR0 doesn't reset to 0 on a EQU0 compare match, rather TA0R does

2) The CCIFG appears to be always-on since SMCLK continues to count during a breakpoint. I'm pretty sure there's a check-box to make it not do that, but I wasn't able to find it just now. If you add ID=3 to the configuration, you'll be able to see the LED blink, which demonstrates that the ISR is resetting CCIFG:

>TIMER_A0->CTL = TIMER_A_CTL_SSEL__SMCLK | TIMER_A_CTL_ID_3 |TIMER_A_CTL_MC__UP;// SMCLK, UP mode

3) I suspect your traceback to c_init is also a debugger illusion, since it can't figure out the traceback from an ISR. (I didn't see it just now, but I have seen it in the past.)

Thanks!

The following is my code. I could not reach 

 P2->OUT ^= BIT0;                        // Toggle P2.0 LED

Please help

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//******************************************************************************
//  MSP432P401 Demo - Timer0_A3, Toggle P1.0, CCR0 Up Mode ISR, DCO SMCLK
//
//  Description: Toggle P1.0 using software and TA_0 ISR. Timer0_A is
//  configured for up mode, thus the timer overflows when TAR counts
//  to CCR0. In this example, CCR0 is loaded with 50000.
//  ACLK = n/a, MCLK = SMCLK = TACLK = default DCO ~3MHz
//
//
//           MSP432P401x
//         ---------------
//     /|\|               |
//      | |               |
//      --|RST            |
//        |               |
//        |           P1.0|-->LED
//
//
//   William Goh
//   Texas Instruments Inc.
//   Oct 2016 (updated) | November 2013 (created)
//   Built with CCSv6.1, IAR, Keil, GCC
//******************************************************************************
#include "ti/devices/msp432p4xx/inc/msp.h"

int main(void) {
    WDT_A->CTL = WDT_A_CTL_PW |             // Stop WDT
            WDT_A_CTL_HOLD;

    // Configure GPIO
    P1->DIR |= BIT0;
    P1->OUT |= BIT0;

    P2->DIR |= BIT0;
    P2->OUT |= BIT0;

    SCB->SCR |= SCB_SCR_SLEEPONEXIT_Msk;    // Enable sleep on exit from ISR

    // Ensures SLEEPONEXIT takes effect immediately
    __DSB();

    // Enable global interrupt
    __enable_irq();

    NVIC->ISER[0] = 1 << ((TA0_0_IRQn) & 31);

    TIMER_A0->CCTL[0] &= ~TIMER_A_CCTLN_CCIFG;
    TIMER_A0->CCTL[0] = TIMER_A_CCTLN_CCIE; // TACCR0 interrupt enabled
    TIMER_A0->CCR[0] = 50000;
   // TIMER_A0->CTL = TIMER_A_CTL_SSEL__SMCLK | // SMCLK, UP mode
         //   TIMER_A_CTL_MC__UP;
    TIMER_A0->CTL = TIMER_A_CTL_SSEL__SMCLK | TIMER_A_CTL_ID_3 |TIMER_A_CTL_MC__UP;// SMCLK, UP mode

    while(1)
    {

        P2->OUT ^= BIT0;                        // Toggle P2.0 LED
    }
  //  __sleep();
  //  __no_operation();
}
// Timer A0_0 interrupt service routine

void TA0_0_IRQHandler(void) {
    // Clear the compare interrupt flag
    TIMER_A0->CCTL[0] &= ~TIMER_A_CCTLN_CCIFG;

    P1->OUT ^= BIT0;                        // Toggle P1.0 LED
}

Thanks

I still feel confused.

Why I could not reach 

 P2->OUT ^= BIT0;                        // Toggle P2.0 LED

>   SCB->SCR |= SCB_SCR_SLEEPONEXIT_Msk;    // Enable sleep on exit from ISR

This is causing main to stop forever (after the first interrupt). I recommend you remove it. It wasn't wrong with the original code, but with your change now it's wrong.

> The interrupt controller automatically clears the interrupt flag as soon as it enters the ISR.

I hesitate to disagree with Seong Kim, but this is not the case for the MSP432 TimerA. It is true for the MSP430 TimerA.

[Edit: Changed "was" to "is" since the MSP430 still, um, "is".]