PIC单片机外部中断

ORG  000HGOTO A1ORG  04HGOTO ZD01A1   BSF  STATUS,RP0BCF  STATUS,RP1;体1MOVLW 0HMOVWF TRISA;设置A口为输出口MOVLW   06H  MOVWF   ADCON1;设置A口为普通I/O口模式 movlw 0FFHmovwf TRISB;设定RB为输入BCF  STATUS,RP0BCF  STATUS,RP1;体0MOVLW 0FFHMOVWF PORTA;A口输出高电平BCF  INTCON,INTF;清中断标志BSF  INTCON,INTE;开外部中断BSF  INTCON,GIE;开总中断GOTO $ZD01  BTFSS INTCON,INTF;判断是否发生外部中断GOTO ZD02 BCF  INTCON,INTF;清中断标志BTFSS PORTB,0;;判断触发中断键是否抬起避免产生2次中断GOTO $-1;COMF PORTA,1;取反A口ZD02 RETFIE ;中断标志END#INCLUDE"P16F877.inc"ORG  000HGOTO A1ORG  004H;定时中断入口地址 GOTO ZD01;ORG  0CHA1   MOVLW 1;位1显示数MOVWF 50H; MOVLW 2;位2显示数MOVWF 51H;MOVLW 3;位3显示数MOVWF 52H;MOVLW 4;位4显示数MOVWF 53H;MOVLW 4;显示位数MOVWF 40H;MOVLW B00000001;位码MOVWF 41H;MOVLW 50H;MOVWF FSR ;间接寻址BSF  STATUS,RP0;选择体1BCF  STATUS,RP1;MOVLW 00H;1:2TMRO比例MOVWF OPTION_REG;分频1/2BCF  STATUS,RP0;体0BCF  STATUS,RP1;MOVLW 0FFH;MOVFW TMR0;初值BCF  INTCON,T0IF;清定时中断标志BSF  INTCON,T0IE;开定时中断BSF  INTCON,GIE;开总中断A2   BTFSC PORTD,4GOTO A3MOVLW 1MOVWF 50HA3   BTFSC PORTD,5GOTO A4MOVLW 2MOVWF 50HA4   BTFSC PORTD,6GOTO A5MOVLW 3MOVWF 50HA5   BTFSC PORTD,7GOTO A6MOVLW 4MOVWF 50HA6   GOTO A2ZD01  BCF  INTCON,GIE;关总中断BTFSS INTCON,T0IF;判断是否产生定时中断GOTO ZD03;否跳出是继续执行BCF  INTCON,T0IFBSF  STATUS,RP0;体1BCF  STATUS,RP1;MOVLW 0;MOVWF TRISC;RB口设为输出口MOVLW B11110000MOVWF TRISD;RD口设为输出口BCF  STATUS,RP0;体0BCF  STATUS,RP1;MOVLW 0FFH;MOVWF PORTC;RB口输出高电平MOVLW 0MOVWF PORTD;RD口输出低电平起清屏作用MOVFW INDF;间接寻址显示数据  CALL Q1;查数据表MOVWF PORTC;显示断码输出到RB口INCF FSR,1;间接寻址地址加1MOVFW 41H ;位码MOVWF PORTD;位码输出到RD口RLF  41H,0;处理CRLF  41H,1;左移位码DECFSZ 40H,1;判断是否显示完4位GOTO ZD02;否则继续显示MOVLW 4;显示位数MOVWF 40H;MOVLW B00000001;位码MOVWF 41H;MOVLW 50H;MOVWF FSR ;间接寻址ZD02  MOVLW 0FFH;MOVFW TMR0;重装初值ZD03  BSF  INTCON,GIE;开总中断RETFIE ;中断返回;********************************************;    数据表;********************************************      Q1   ADDWF   PCL,1  RETLW     00C0H        ;0RETLW     00F9H        ;1RETLW     00A4H        ;2RETLW     00B0H        ;3RETLW     0099H        ;4RETLW     0092H        ;5RETLW     0082H        ;6RETLW     00F8H        ;7RETLW     0080H        ;8RETLW     0090H        ;9RETLW     0088H        ;ARETLW     0083H        ;BRETLW     00C6H        ;CRETLW     00A1H        ;DRETLW     0086H        ;ERETLW     008EH        ;FEND