MSP430F5438A: Port interrupt

Hello,

Are you enabling interrupts on pins that you use for interrupts? Also, are you clearing the interrupt flags immediately after enabling the interrupts for each IO pin and are you clearing the interrupt flags in the ISRs? According to the user's guide, writing to P1OUT, P1DIR, P1REN, P2OUT, P2DIR, or P2REN can result in setting the corresponding P1IFG or P2IFG flags.

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//******************************************************************************
//  MSP430F543xA Demo - Software Port Interrupt Service on P1.4 from LPM4 with
//                    Internal Pull-up Resistance Enabled
//
//  Description: A hi "TO" low transition on P1.4 will trigger P1_ISR which,
//  toggles P1.0. P1.4 is internally enabled to pull-up. Normal mode is
//  LPM4 ~ 0.1uA. LPM4 current can be measured with the LED removed, all
//  unused Px.x configured as output or inputs pulled high or low.
//  ACLK = n/a, MCLK = SMCLK = default DCO
//
//               MSP430F5438A
//            -----------------
//        /|\|              XIN|-
//         | |                 |
//         --|RST          XOUT|-
//     /|\   |                 |
//      --o--|P1.4         P1.0|-->LED
//     \|/
//
//   M. Morales
//   Texas Instruments Inc.
//   June 2009
//   Built with CCE Version: 3.2.2 and IAR Embedded Workbench Version: 4.11B
//******************************************************************************

#include <msp430.h>

int main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop watchdog timer
  P1DIR |= 0x01;                            // Set P1.0 to output direction
  P1REN |= 0x10;                            // Enable P1.4 internal resistance
  P1OUT |= 0x10;                            // Set P1.4 as pull-Up resistance
  P1IE |= 0x10;                             // P1.4 interrupt enabled
  P1IES |= 0x10;                            // P1.4 Hi/Lo edge
  P1IFG &= ~0x10;                           // P1.4 IFG cleared

  __bis_SR_register(LPM4_bits + GIE);       // Enter LPM4 w/interrupt
  __no_operation();                         // For debugger
}

// Port 1 interrupt service routine
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=PORT1_VECTOR
__interrupt void Port_1(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(PORT1_VECTOR))) Port_1 (void)
#else
#error Compiler not supported!
#endif
{
  P1OUT ^= 0x01;                            // P1.0 = toggle
  P1IFG &= ~0x010;                          // P1.4 IFG cleared
}