多个按键控制LED程序

 1     KEY_COMMON    bit    P3.2　　　　；按键公共端
 2     KEY_1        bit    p0.5　　　　　；三个按键
 3     KEY_2        bit    p0.4
 4     KEY_3        bit    p0.3
 5 
 6     BEEP        bit    p2.0　　　　  ；蜂鸣器
 7 
 8     LED_1        bit    p1.7　　　　；六个LED灯
 9     LED_2        bit    p1.6
10     LED_3        bit    p1.5
11     LED_4        bit    p1.4
12     LED_5        bit    p1.3
13     LED_6        bit    p1.2
14 
15     org    0000H        
16     jmp    MAIN
17 
18 ;*******************************************    
19     org    0030H        ;Start program from 0030H        
20 MAIN:
21     mov    P0,#0FFH    ;Initialize the port，初始化端口 
22     mov    P1,#0FFH    
23     mov    P2,#0FFH    
24     mov    P3,#0FFH
25     
26     clr    KEY_COMMON    ;Clear the common line
27 MAIN_LOOP:
28     jb    KEY_1,LAB_KEY_2    ;Wait for key down，按下按键1条跳到LAB_KEY_2，一个都没按做循环直到按了按键

29     call    DELAY
30     cpl    LED_1        ;Change the state of LED8，（累加器求反）
31     cpl    LED_2        ;Change the state of LED7
32     jmp    NEXT_LOOP
33     
34 LAB_KEY_2:
35     jb    KEY_2,LAB_KEY_3    ;Wait for key down
36     call    DELAY
37     cpl    LED_3        ;Change the state of LED6
38     cpl    LED_4        ;Change the state of LED5
39     jmp    NEXT_LOOP    
40     
41 LAB_KEY_3:
42     jb    KEY_3,NEXT_LOOP    ;Wait for key down
43     call    DELAY
44     cpl    LED_5        ;Change the state of LED4
45     cpl    LED_6        ;Change the state of LED3
46     jmp    NEXT_LOOP
47 
48 NEXT_LOOP:
49 
50     jmp    MAIN_LOOP
51 
52 ret    
53 ;****************************************************
54 DELAY:
55     mov    r7,#200
56 DELAY_LOOP:
57     mov    r6,#200
58     djnz    r6,$
59     mov    r6,#200
60     djnz    r6,$
61 
62     djnz    r7,DELAY_LOOP
63 ret
64 ;****************************************************
65     END