CCS/MSP430G2553: Questions on how to implement a interrupt push button

Hi,

You can refer to MSP code example for help. Below is exmaple code for using GPIO as input interrupt. 

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; ******************************************************************************
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;                        MSP430 CODE EXAMPLE DISCLAIMER
;
;  MSP430 code examples are self-contained low-level programs that typically
;  demonstrate a single peripheral function or device feature in a highly
;  concise manner. For this the code may rely on the device's power-on default
;  register values and settings such as the clock configuration and care must
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;  effects. Also see www.ti.com/grace for a GUI- and www.ti.com/msp430ware
;  for an API functional library-approach to peripheral configuration.
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; --/COPYRIGHT--
;******************************************************************************
;  MSP430FR243x Demo - Software Port Interrupt Service on P1.3 from LPM3
;
;  Description: A Hi/Lo transition on P1.3 will trigger P1ISR the first time.
;  On hitting the P1ISR, device exits LPM3 mode and executes section of code in
;  main() which includes toggling an LED.
;
;  ACLK = default REFO ~32768Hz, MCLK = SMCLK = default DCODIV ~1MHz
;
;               MSP430FR2433
;            -----------------
;        /|\|                 |
;         | |                 |
;         --|RST              |
;           |                 |
;     /|\   |                 |
;      --o--|P1.3         P1.0|-->LED
;     \|/   |                 |
;           |                 |
;
;   Cen Fang
;   Wei Zhao
;   Texas Instruments Inc.
;   September 2013
;   Built with IAR Embedded Workbench v6.20
;******************************************************************************
#include <msp430.h>
;-------------------------------------------------------------------------------
            RSEG    CSTACK                  ; Define stack segment
;-------------------------------------------------------------------------------
            RSEG    CODE
;-------------------------------------------------------------------------------
RESET       mov.w   #SFE(CSTACK),SP         ; Initialize stackpointer
            mov.w   #WDTPW+WDTHOLD,&WDTCTL  ; Stop WDT

SetupP1     bic.b   #BIT0,&P1OUT            ; Clear P1.0 output
            bis.b   #BIT0,&P1DIR            ; P1.0 output

            bis.b   #BIT3,&P1OUT            ; Configure P1.3 as pulled-up
            bis.b   #BIT3,&P1REN            ; P1.3 pull-up register enable
            bis.b   #BIT3,&P1IES            ; P1.3 Lo/Hi edge
            bis.b   #BIT3,&P1IE             ; P1.3 interrupt enabled

            bic.w   #LOCKLPM5,PM5CTL0       ; Unlock I/O pins
            
            bic.b   #BIT3,&P1IFG            ; P1.3 IFG cleared

Mainloop    bis.w   #LPM3+GIE,SR            ; Enter LPM3 w/ interrupt
            nop                             ; for debug
            xor.b   #BIT0,&P1OUT            ; P1.0 = toggle
            jmp     Mainloop

;------------------------------------------------------------------------------
P1_ISR ;    Port 1 Interrupt
;------------------------------------------------------------------------------
            bic.b   #BIT3,&P1IFG            ; Clear P1.3 IFG
            bic.w   #LPM3,0(SP)             ; Exit LPM3
            reti
;-------------------------------------------------------------------------------
            COMMON  INTVEC                  ; Interrupt Vectors
;-------------------------------------------------------------------------------
            ORG     RESET_VECTOR            ; POR, ext. Reset
            DW      RESET
            ORG     PORT1_VECTOR            ; Port 1 Vector
            DW      P1_ISR
            END

Best Regards,

Winter Yu