External interrupt at port 1
Basic Steps
- Enable global interrupt(eint)
- Enable external interrupt (on p1.4–P1IE)
- select interrupt edge (IP1IES)
- clear P1IFG flag starting the program
- clear P1IFG flag in your interrupt service routine
.include "msp430g2x31.inc"
org 0xf800
mov.w #(WDTPW|WDTHOLD), &WDTCTL
mov.w #0x280, SP
mov.b #0x10, P1REN
CLR.B P1OUT
mov.b #001h,&P1DIR
bis.b #010h,&P1IE ;enable interrupt on p1.4
bis.b #010h,&P1IES ;select -ve edge
bic.b #010h,&P1IFG ;clear interuupt flag
eint ;enables interrup
gg:jmp gg
P1ISR: mov.b #001h,&P1OUT
bic.b #010h,&P1IFG
reti
ORG 0FFE4h
DW P1ISR
ORG 0FFFEh
DW 0xf800
Basic Steps
- Enable global interrupt(eint)
- Enable external interrupt (on p1.4–P1IE)
- select interrupt edge (IP1IES)
- clear P1IFG flag starting the program
- clear P1IFG flag in your interrupt service routine
.include "msp430g2x31.inc"
org 0xf800
mov.w #(WDTPW|WDTHOLD), &WDTCTL
mov.w #0x280, SP
mov.b #0x10, P1REN
CLR.B P1OUT
mov.b #001h,&P1DIR
bis.b #010h,&P1IE ;enable interrupt on p1.4
bis.b #010h,&P1IES ;select -ve edge
bic.b #010h,&P1IFG ;clear interuupt flag
eint ;enables interrup
gg:jmp gg
P1ISR: mov.b #001h,&P1OUT
bic.b #010h,&P1IFG
reti
ORG 0FFE4h
DW P1ISR
ORG 0FFFEh
DW 0xf800
