Đã giải quyết xong. Đây là CODE ASEMBLY
processor p16f877a
include <p16f877a.inc>
__CONFIG _CP_OFF & _WDT_OFF & _BODEN_OFF & _PWRTE_ON & _XT_OSC & _WRT_OFF & _LVP_ON & _CPD_OFF
;KHAI BAO BIEN
#DEFINE CB1 PORTB,0
#DEFINE CB2 PORTB,1
#DEFINE CB3 PORTB,2
#DEFINE CB4 PORTB,3
#DEFINE BOM PORTB,4
#DEFINE LED PORTB,5
;CHUONG TRINH CHINH
ORG 0X0000
GOTO START
START
BCF STATUS,RP1
BCF STATUS,RP0
CLRF PORTD
CLRF PORTB
BSF STATUS,RP0
MOVLW B'00001111'
MOVWF TRISB
MOVLW 0X00
MOVWF TRISD
BCF STATUS,RP0
CLRF PORTB
CLRF PORTD
;VONG LAP
LAP
BTFSS CB1
GOTO BAT_BOM
BTFSS CB2
GOTO XUAT_E
BTFSS CB3
GOTO XUAT_L
BTFSS CB4
GOTO XUAT_H
GOTO XUAT_F
BAT_BOM
MOVLW B'1000000'
MOVWF PORTD
BSF BOM
GOTO LAP
XUAT_E
MOVLW B'0000110'
MOVWF PORTD
GOTO LAP
XUAT_L
MOVLW B'1000111'
MOVWF PORTD
GOTO LAP
XUAT_H
MOVLW B'0001001'
MOVWF PORTD
GOTO LAP
XUAT_F
MOVLW B'0001110'
MOVWF PORTD
BCF BOM
GOTO LAP
END