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PIC单片机

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

list p=16f870

#include

; __CONFIG _CP_OFF & _WDT_ON & _BODEN_ON & _PWRTE_ON & _RC_OSC & _WRT_ENABLE_ON & _LVP_OFF & _CPD_OFF

FLAG EQU 0x20

Var1 EQU 0x21

Var2 EQU 0x22

INT_Var1 EQU 0x30

INT_Var2 EQU 0x31

W_Temp EQU 0x72

STATUS_Temp EQU 0x73

FSR_Temp EQU 0x74

#define VAL_1MS .248

#define FLAG_INC 0

#define FLAG_DEC 1

org 0x00 ; RESET  0x000

nop

clrf PCLATH

goto Main

org 0x004

INT_ISRs

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

movwf W_Temp ; save off current W register contents

movf STATUS,W ; move status register into W register

bcf STATUS,RP0 ; ensure file register bank set to 0

movwf STATUS_Temp ; save off contents of STATUS register

movf FSR,W

movwf FSR_Temp

BANKSEL PORTB

movf PORTB,W

bcf INTCON,RBIF

bcf INTCON,RBIE ; RBIE Disable

call Bounce_Delay



btfsc PORTB,4

goto Check_DEC_KEY

bsf FLAG,FLAG_INC ; FLAG_INC  1

goto Exit_ISRs

Check_DEC_KEY

btfss PORTB,5

bsf FLAG,FLAG_DEC

Exit_ISRs

movf FSR_Temp,W

movwf FSR

bcf STATUS,RP0 ; ensure file register bank set to 0

movf STATUS_Temp,w ; retrieve copy of STATUS register

movwf STATUS ; restore pre-isr STATUS register contents

swapf W_Temp,F

swapf W_Temp,W ; restore pre-isr W register contents

retfie ; return from interrupt

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

;**** Delay 10 ms 

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

Bounce_Delay

movlw .10

movwf INT_Var1

Bounce_Loop1

movlw .248

movwf INT_Var2

Bounce_Loop2

nop

decfsz INT_Var2,F

goto Bounce_Loop2

decfsz INT_Var1,F

goto Bounce_Loop1

return

******************************************

Main

BANKSEL TRISB

movlw B'11110000'

movwf TRISB ; RB4..RB7

clrf TRISC

movlw B'00000000' ; Enable PORTB  Pull UP

movwf OPTION_REG

BANKSEL PORTB

movlw B'11111111'

movwf PORTB

clrf PORTC

bsf INTCON,GIE

clrf FLAG

bsf FLAG,FLAG_INC

Prog_Loop

btfss FLAG,FLAG_INC

goto Dec_Process

Inc_Process

call Delay_50ms

incfsz PORTC,F

goto Inc_Process

goto SLEEP_Process

Dec_Process

call Delay_50ms

decfsz PORTC,F

goto Dec_Process

SLEEP_Process

clrf PORTC

clrf FLAG

movf PORTB,W

bcf INTCON,RBIF

bsf INTCON,RBIE

SLEEP

nop

nop

goto Prog_Loop

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

;**** Delay 50ms 

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

Delay_50ms

movlw .50

movwf Var2

Delay_200ms_Loop

call Delay_1ms

decfsz Var2,F

goto Delay_200ms_Loop

return

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

;**** Delay 1ms 

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

Delay_1ms

nop

nop

nop

movlw VAL_1MS

movwf Var1

Delay_1ms_Loop nop

decfsz Var1,F

goto Delay_1ms_Loop

return

END