MÌNH DÙNG 555 PHÁT XUNG ĐƯA VÀO RC2,DƯỚI ĐÂY LÀ ĐOẠN CODE
__CONFIG _CP_OFF & _WDT_OFF & _PWRTE_ON & _HS_OSC & _LVP_OFF & _BODEN_OFF & _WRT_OFF & _CPD_OFF
PROCESSOR P16F877A
#INCLUDE <P16F877A.INC>
PB EQU PORTB
PC EQU PORTC
TB EQU TRISB
TC EQU TRISC
PD EQU PORTD
TD EQU TRISD
B0 EQU 0X00
B1 EQU 0X80
ORG 0X00
GOTO MAIN
ORG 0X04
GOTO NGAT
NGAT
BCF STATUS,RP0
BTFSC PIR1,CCP1IF
GOTO CAPTURE
BTFSC PIR1,TMR1IF
GOTO TMR
ERROR1
BSF PD,1
BCF PD,1
GOTO ERROR1
TMR
BCF PIR1,TMR1IF
RETFIE
;-------------------------------
;NGAT DO CAPTURE
;-------------------------------
CAPTURE
MOVLW B'11111111'
MOVWF PB
RETFIE
;------------------------------
;MAIN
;------------------------------
MAIN
BANKSEL B0
CLRF PB
CLRF PC
CLRF PD
CLRF INTCON
CLRF PIR1
BANKSEL B1
CLRF TB
CLRF TD
BSF TC,2
MOVLW 0X06
CLRF ADCON1
CLRF PIE1
BSF PIE1,CCP1IE
BSF PIE1,TMR1IE
BANKSEL B0
CLRF TMR1L
CLRF TMR1H
MOVLW 0X30
MOVWF T1CON
BSF INTCON,PEIE
BSF INTCON,GIE
MOVLW b'00000101'
MOVWF CCP1CON
BSF T1CON,TMR1ON
loop
GOTO loop
END