我正在尝试闪烁D0，但D0仅保持点亮状态。我该如何解决？
list r=dec
include P16f684.inc
__CONFIG _FCMEN_OFF & _IESO_OFF & _BOD_OFF & _CPD_OFF & _CP_OFF & _MCLRE_OFF & _PWRTE_ON & _WDT_OFF & _INTOSCIO
Cblock 0x20 ; start of GPR
count ;
endc ; This directive must be
; supplied to terminate the
; cblock list
;
;
; ----- main program --------------
org 0x000 ; Hex address 0x000, the first
; program memory location
;
start BCF STATUS,RP0 ; Select Bank 0
;
CLRF PORTA ; Initialize PORTA (all zeros)
;
MOVLW 7 ; Load w with 7
MOVWF CMCON0 ; Load CMCON0 with 7
; Turns off comparators
;
BSF STATUS,RP0 ; Select Bank 1
;
CLRF ANSEL ; Shut off ADC (digital I/O)
;
MOVLW b'001111' ; Load w ? RA4 and RA5 outputs
MOVWF TRISA ; copy w to TRIS PORTA
;
BCF STATUS,RP0 ; Select Bank 0
;
Loop BSF PORTA,4 ; Make RA4 high -- D0 ON
;
CALL Delay ; Goto the delay routine
;
BCF PORTA,4 ; Make RA4 low -- D0 OFF
;
CALL Delay ; Goto the delay routine
;
GOTO Loop ; Do it again
;
;
Delay MOVLW 10 ; Decimal 10
MOVWF count ; Initialize counter to 10
Repeat DECFSZ count,f ; Decrement counter
GOTO Repeat ; If counter <> 0
RETURN ; If counter = 0 (end delay)
;
end