电路图：
扫描原理：
逐列扫描，先将第一列输出低，其他所有IO设置为上拉输入，读取IO值，高4位哪个为低，说明是当前列哪个按键按下。
源码：
1 /***************************************************************************** 2 * FILE NAME keypad.h 3 * DESCRIPTION: 4 * Copyright : xxx Technologies Ltd. 5 * All Rights Reserved 6 * Author: Milo lu 7 * Copyright (c) 2021, PGST Technologies Ltd. 8 * 9 * All rights reserved. 10 -* ****************************************************************************/ 11 #ifndef __KEYPAD_H 12 #define __KEYPAD_H 13 14 //--------------------- Keys Macro Define ----------------------- 15 #define KEY_0 BIT0 16 #define KEY_1 BIT1 17 #define KEY_2 BIT2 18 #define KEY_3 BIT3 19 #define KEY_4 BIT4 20 #define KEY_5 BIT5 21 #define KEY_6 BIT6 22 #define KEY_7 BIT7 23 #define KEY_8 BIT8 24 #define KEY_9 BIT9 25 #define ASTERIK_KEY BIT10 26 #define POUND_KEY BIT11 27 #define ARM_KEY BIT12 28 #define DISARM_KEY BIT13 29 #define HOME_KEY BIT14 30 #define SOS_KEY BIT15 31 32 33 void keypad_init(void); 34 u16 keypad_scan(void); 35 36 #endif 37 38 //------------------------------ end of file ------------------------------keypad.h
1 /*****************************************************************************
2 * FILE NAME keypad.c
3 * DESCRIPTION:
4 * Copyright : xxxTechnologies Ltd.
5 * All Rights Reserved
6 * Author: Milo lu
7 * Copyright (c) 2021, PGST Technologies Ltd.
8 *
9 * All rights reserved.
10 -* ****************************************************************************/
11 //---------------- system --------------------------
12 #include "Global.h"
13
14 //---------------- Peripheral ----------------------
15 #include "keypad.h"
16
17
18
19 u16 g_key_value;
20
21 /**
22 * @brief keypad_init
23 */
24 void keypad_init(void)
25 {
26 int i;
27 for(i=0;i<8;i++) //PB1-PB8 set input with pull-up
28 {
29 GPIO_Init(GPIOB,i+1,0,1,0,0);
30 }
31 }
32
33 /**
34 * @brief keypad_scan
35 * @return key value
36 */
37 u16 keypad_scan(void)
38 {
39 u8 io_state;
40
41 u16 key_value = 0;
42
43 //---------------------- Read [1,4,7,*] keys ---------------------------
44 GPIO_Init(GPIOB,PIN1,1,0,0,0); //the first column
45 vTaskDelay(2);
46 io_state = (GPIOB->IDR>>1)&0xF0; //get io state
47 if(io_state!=0xF0) //is any key press in the frist column?
48 {
49 vTaskDelay(20); //debouncing
50 io_state = (GPIOB->IDR>>1)&0xF0; //get io state again
51 if(io_state!=0xF0) //is any key press? [1,4,7,*]
52 {
53 if((io_state&BIT7)==0)
54 {
55 key_value |= KEY_1;
56 }
57 if((io_state&BIT6)==0)
58 {
59 key_value |= KEY_4;
60 }
61 if((io_state&BIT5)==0)
62 {
63 key_value |= KEY_7;
64 }
65 if((io_state&BIT4)==0)
66 {
67 key_value |= ASTERIK_KEY;
68 }
69 }
70 }
71 GPIO_Init(GPIOB,PIN1,0,1,0,0); //release,input with pull-up
72
73 //---------------------- Read [2,5,8,0] keys ---------------------------
74 GPIO_Init(GPIOB,PIN2,1,0,0,0); //the second column
75 vTaskDelay(2);
76 io_state = (GPIOB->IDR>>1)&0xF0; //get io state
77 if(io_state!=0xF0) //is any key press in the second column?
78 {
79 vTaskDelay(20); //debouncing
80 io_state = (GPIOB->IDR>>1)&0xF0; //get io state again
81 if(io_state!=0xF0) //is any key press? [2,5,8,0]
82 {
83 if((io_state&BIT7)==0)
84 {
85 key_value |= KEY_2;
86 }
87 if((io_state&BIT6)==0)
88 {
89 key_value |= KEY_5;
90 }
91 if((io_state&BIT5)==0)
92 {
93 key_value |= KEY_8;
94 }
95 if((io_state&BIT4)==0)
96 {
97 key_value |= KEY_0;
98 }
99 }
100 }
101 GPIO_Init(GPIOB,PIN2,0,1,0,0); //release,input with pull-up
102
103 //---------------------- Read [3,6,9,#] keys ---------------------------
104 GPIO_Init(GPIOB,PIN3,1,0,0,0); //the third column
105 vTaskDelay(2);
106 io_state = (GPIOB->IDR>>1)&0xF0; //get io state
107 if(io_state!=0xF0) //is any key press in the second column?
108 {
109 vTaskDelay(20); //debouncing
110 io_state = (GPIOB->IDR>>1)&0xF0; //get io state again
111 if(io_state!=0xF0) //is any key press? [3,6,9,#]
112 {
113 if((io_state&BIT7)==0)
114 {
115 key_value |= KEY_3;
116 }
117 if((io_state&BIT6)==0)
118 {
119 key_value |= KEY_6;
120 }
121 if((io_state&BIT5)==0)
122 {
123 key_value |= KEY_9;
124 }
125 if((io_state&BIT4)==0)
126 {
127 key_value |= POUND_KEY;
128 }
129 }
130 }
131 GPIO_Init(GPIOB,PIN3,0,1,0,0); //release,input with pull-up
132
133 //---------------------- Read [arm,diarm,home,sos] keys ---------------------------
134 GPIO_Init(GPIOB,PIN4,1,0,0,0); //the fourth column
135 vTaskDelay(2);
136 io_state = (GPIOB->IDR>>1)&0xF0; //get io state
137 if(io_state!=0xF0) //is any key press in the second column?
138 {
139 vTaskDelay(20); //debouncing
140 io_state = (GPIOB->IDR>>1)&0xF0; //get io state again
141 if(io_state!=0xF0) //is any key press? [arm,diarm,home,sos]
142 {
143 if((io_state&BIT7)==0)
144 {
145 key_value |= ARM_KEY;
146 }
147 if((io_state&BIT6)==0)
148 {
149 key_value |= DISARM_KEY;
150 }
151 if((io_state&BIT5)==0)
152 {
153 key_value |= HOME_KEY;
154 }
155 if((io_state&BIT4)==0)
156 {
157 key_value |= SOS_KEY;
158 }
159 }
160 }
161 GPIO_Init(GPIOB,PIN4,0,1,0,0); //release,input with pull-up
162
163 return key_value;
164 }
165
166
167
168
169
170
171
172
173
174
175
176 //--------------------- end of file ------------------------------
keypad.c
仅供参考，请勿用于商业。谢谢