大家好 有關之前按鍵與震盪器的問題已順利解決 謝謝大家的協助 目前遇到的困難是 當我想以按下按鍵的次數來累加LED發光的秒數 但是結果都只會計數原來暫存器存的10秒 並沒有累加的功能 以下是我的程式 請各位幫我看看 謝謝
list p=16F873a
#include <p16f873a.inc> ; Include file locate at defult directory

VAL_500uS equ .250 ; 0.5ms delay value
VAL_1s equ .200 ; 10mS delay value

count_1m equ 0x22
count_5s equ 0x23
count_1s equ 0x24
count_us equ 0x25
Reg_time equ 0x26

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


;*********************************************
org 0x00
nop
initial:

;bcf STATUS,RP0
;bcf STATUS,RP1
;clrf PORTA
;bsf STATUS,RP0
banksel ADCON1 ;定義ADCCON1，將PORTA第四個bit設為數位模式
movlw b'11000110'

movwf ADCON1

banksel CMCON ;定義CMCON將比較器功能關閉
movlw b'00000111'
movwf CMCON
movlw b'00011000'
movwf TRISA

banksel TRISB ;定義TRISB設定PORTB為輸出模式
clrf TRISB

banksel PORTB
clrf PORTB



;***********************************************
Main
;***********************************************
start:
clrf Reg_time
movlw b'11111111' ;LED初始狀態
movwf PORTB
movlw .10
movwf Reg_time


;--------------------------------------------------------

key_time:
btfsc PORTA,4
goto key_enter
;goto key_time
goto add_time

add_time:

addwf Reg_time,1
goto key_time

key_enter:
btfsc PORTA,5
goto key_time
;goto key_enter
goto enter_mode


enter_mode:
call delay_1s
movlw b'00000000'
movwf PORTB

decfsz Reg_time
goto enter_mode
goto clear_mode
clear_mode:



movlw b'11111111'
movwf PORTB
goto start

;-----------------------延遲1s-------------------------------------------
delay_1s:
movlw VAL_1s
movwf count_1s
loop_1s call delay_0.5ms
decfsz count_1s,F
goto loop_1s
return
;-----------------------延遲0.5ms----------------------------------------
delay_0.5ms:
movlw VAL_500uS
movwf count_us
dec_loop nop
nop`
nop
nop
nop
decfsz count_us,F
goto dec_loop
return
;---------------------------------------------------------------------------

end