Question

用AT89C51控制ADC0808将模拟信号转换为数值，范围0-225，再控制LED数码管以16进制实时的显示出来

Answer 1

LED_0 EQU 30H
LED_1 EQU 31H
LED_2 EQU 32H ;存放段码
ADC EQU 35H
CLOCK BIT P2.4 ;定义ADC0808时钟位
ST BIT P2.5
EOC BIT P2.6
OE BIT P2.7

ORG 00H
SJMP START
ORG 0BH
LJMP INT_T0

START:
MOV LED_0,#00H
MOV LED_1,#00H
MOV LED_2,#00H
MOV DPTR,#TABLE ;段码表首地址
MOV TMOD,#02H
MOV TH0,#245
MOV TL0,#00H
MOV IE,#82H
SETB TR0

WAIT: CLR ST
SETB ST
CLR ST ;启动AD转换
JNB EOC,$ ;等待转换结束
SETB OE
MOV ADC,P1 ;读取AD转换结果
CLR OE
MOV A,ADC
MOV 34H,A
MOV B,#100 ;AD转换结果转换成BCD码
DIV AB
MOV LED_2,A
MOV A,B
MOV B,#10
DIV AB
MOV LED_1,A
MOV LED_0,B
LCALL DISP
SJMP WAIT

INT_T0: CPL CLOCK ;提供ADC0808时钟信号
RETI

DISP: MOV A,LED_0 ;显示子程序
MOVC A,@A+DPTR
CLR P2.3
MOV P0,A
LCALL DELAY
SETB P2.3

MOV A,LED_1
MOVC A,@A+DPTR
CLR P2.2
MOV P0,A
LCALL DELAY
SETB P2.2

MOV A,LED_2
MOVC A,@A+DPTR
CLR P2.1
MOV P0,A
LCALL DELAY
SETB P2.1
RET

DELAY: MOV R6,#10 ;延时5毫秒
D1: MOV R7,#250
DJNZ R7,$
DJNZ R6,D1
RET

TABLE: DB 3FH,06H,5BH,4FH,66H
DB 6DH,7DH,07H,7FH,6FH
END