2.9 用74HC165读8个按键状态
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1 //--------------------------------------------------------------------------
2 //来源: http://hi.baidu.com/mculove/home
3 //程序名称: 用74HC165读8个按键状态
4 //晶振: 11.0592MHz;
5 //MCU型号: STC89C52RC;
6 //电路板型号: EBV-MV(51实验板);
7 //--------------------------------------------------------------------------
8
9
10
11
12 //--------------------------------------------------------------------------
13 //硬件连接:
14 //EBVn-[VCC] -> MVn-[--VCC--]
15 //EBVn-[GND] -> MVn-[//GND//]
16 //MVn-{EX3}-[Y0] -> MVn-{EX2}-[L1]
17 //MVn-{EX3}-[Y1] -> MVn-{EX2}-[L2]
18 //MVn-{EX3}-[Y2] -> MVn-{EX2}-[L3]
19 //MVn-{EX3}-[Y3] -> MVn-{EX2}-[L4]
20 //MVn-{EX3}-[Y4] -> MVn-{EX2}-[L5]
21 //MVn-{EX3}-[Y5] -> MVn-{EX2}-[L6]
22 //MVn-{EX3}-[Y6] -> MVn-{EX2}-[L7]
23 //MVn-{EX3}-[Y7] -> MVn-{EX2}-[L8]
24 // -> MVn-{EX2}-(VCC)
25 // -> MVn-{EX3}-(VCC)
26
27 //EBVn-[P10] -> MVn-{EX3}-[A]
28 //EBVn-[P11] -> MVn-{EX3}-[B]
29 //EBVn-[P12] -> MVn-{EX3}-[C]
30 //EBVn-[P13] -> MVn-{EX3}-[G1]
31 //--------------------------------------------------------------------------
32
33
34
35
36 //--------------------------------------------------------------------------
37 //实验结果:
38 //控制74HC138的[A,B,C,G1]端口,使[Y0,Y1..Y7]输出预期的值,LED实现了流水灯显示
39 //--------------------------------------------------------------------------
40
41
42
43 //------------------------------------------------------
44 //头文件;
45 #include <AT89X52.H>
46
47 #define HC165_nPL P3_5
48 #define HC165_CK P3_6
49 #define HC165_OUT P3_7
50
51 //------------------------------------------------------
52 void delay(void)
53 {
54 unsigned char i,j;
55 for(i = 250;i > 0;i--)
56 for(j = 200;j > 0;j--);
57 }
58
59 unsigned char HC165(void)
60 {
61 unsigned char i;
62 unsigned char Temp;
63 HC165_CK = 1;
64 HC165_nPL = 0; //HC165读按键
65 HC165_nPL = 1; //暂停HC165读按键
66 Temp = 0;
67 if(HC165_OUT == 1) Temp |= 0x01;
68 for(i = 0;i < 7;i++)
69 {
70 HC165_CK = 0;
71 HC165_CK = 1;
72 Temp <<= 1;
73 if(HC165_OUT == 1)
74 {
75 Temp |= 0x01;
76 }
77 }
78 HC165_CK = 0;
79 return(Temp);
80 }
81
82
83
84 //------------------------------------------------------
85 //程序入口;
86 void main(void)
87 {
88 while(1)
89 {
90 P1 = HC165();
91 delay();
92 }
93 }
