PIC microcontroller timer interrupt-EEWORLD

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#INCLUDE"P16F877.inc"

ORG 000H

GOTO A1

ORG 004H; timing interrupt entry address

GOTO ZD01;

ORG 0CH

A1 MOVLW 1; bit 1 displays the number

MOVWF 50H;

MOVLW 2; bit 2 displays the number

MOVWF 51H;

MOVLW 3; bit 3 displays the number

MOVWF 52H;

MOVLW 4; bit 4 displays the number

MOVWF 53H;

MOVLW 4; Display digits

MOVWF 40H;

MOVLW B'00000001'; bit code

MOVWF 41H;

MOVLW 50H;

MOVWF FSR ; indirect addressing

BSF STATUS, RP0; select body 1

BCF STATUS,RP1;

MOVLW 00H; 1:2TMRO ratio

MOVWF OPTION_REG; divide by 1/2

BCF STATUS,RP0;body0

BCF STATUS,RP1;

MOVLW 0FFH;

MOVFW TMR0; initial value

BCF INTCON, T0IF; clear the timing interrupt flag

BSF INTCON, T0IE; open timer interrupt

BSF INTCON, GIE; open general interrupt

GOTO $

ZD01 BCF INTCON, GIE; turn off total interrupt

BTFSS INTCON, T0IF; Determine whether a timing interrupt occurs

GOTO ZD03; No, jump out, continue to execute

BCF INTCON,T0IF

BSF STATUS,RP0;body1

BCF STATUS,RP1;

MOVLW 0;

MOVWF TRISB; RB port is set as output port

MOVWF TRISD; RD port is set as output port

BCF STATUS,RP0;body0

BCF STATUS,RP1;

MOVLW 0FFH;

MOVWF PORTB; RB port outputs high level

MOVLW 0

MOVWF PORTD; RD port outputs low level to clear the screen

MOVFW INDF; indirect addressing display data

CALL Q1; check the data table

MOVWF PORTB; Display the broken code output to port RB

INCF FSR,1; Indirect addressing address plus 1

MOVFW 41H ; bit code

MOVWF PORTD; bit code output to RD port

RLF 41H,0; Process C

RLF 41H,1; left shift code

DECFSZ 40H,1; Determine whether the 4 bits are displayed

GOTO ZD02; otherwise continue to display

MOVLW 4; Display digits

MOVWF 40H;

MOVLW B'00000001'; bit code

MOVWF 41H;

MOVLW 50H;

MOVWF FSR ; indirect addressing

ZD02 MOVLW 0FFH;

MOVFW TMR0; reload initial value

ZD03 BSF INTCON, GIE; open general interrupt

RETFIE ;Interrupt return

;********************************************

; data sheet

;********************************************

Q1 ADDWF PCL,1

RETLW 00C0H ;0

RETLW 00F9H ;1

RETLW 00A4H ;2

RETLW 00B0H ;3

RETLW 0099H ;4

RETLW 0092H ;5

RETLW 0082H ;6

RETLW 00F8H ;7

RETLW 0080H ;8

RETLW 0090H ;9

RETLW 0088H ;A

RETLW 0083H ;B

RETLW 00C6H ;C

RETLW 00A1H ;D

RETLW 0086H ;E

RETLW 008EH ;F

END

Reference address：PIC microcontroller timer interrupt

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