实验四 矩阵键盘识别设计
设计要求：
对4×4矩阵式键盘电路的键值进行编码，编程实现在LCD液晶显示器上显示每个按键的“0－F”序号
电路设计：
软件代码:
代码语言：javascript复制#include "hml/hml.h"
#define uchar unsigned char
#define uint unsigned int
#define lcden P1_2
#define lcdrs P1_0
#define rw P1_1
/* IO引脚分配定义 */
#define KEY_IN_1 P2_4 //矩阵按键的扫描输入引脚1
#define KEY_IN_2 P2_5 //矩阵按键的扫描输入引脚2
#define KEY_IN_3 P2_6 //矩阵按键的扫描输入引脚3
#define KEY_IN_4 P2_7 //矩阵按键的扫描输入引脚4
#define KEY_OUT_1 P2_0 //矩阵按键的扫描输出引脚1
#define KEY_OUT_2 P2_1 //矩阵按键的扫描输出引脚2
#define KEY_OUT_3 P2_2 //矩阵按键的扫描输出引脚3
#define KEY_OUT_4 P2_3 //矩阵按键的扫描输出引脚4
#define LSA P1_5 //LED位选译码地址引脚A
#define LSB P1_6 //LED位选译码地址引脚B
#define LSC P1_7 //LED位选译码地址引脚C
unsigned char disBuf=0;
uchar table1[] = "Welcome To CSLG!";
uchar table2[] = "0123456789ABCDEF";
uchar table3[] = " ";
uchar num;
const unsigned char KeyCodeMap[4][4] = { //矩阵按键到标准键码的映射表
{ '0', '1', '2', '3' }, //
{ '4', '5', '6', '7' }, //
{ '8', '9', 'a', 'b' }, //
{ 'c', 'd', 'e', 'f' } //
};
unsigned char KeySta[4][4] = { //全部矩阵按键的当前状态
{1, 1, 1, 1}, {1, 1, 1, 1}, {1, 1, 1, 1}, {1, 1, 1, 1} };
/* 函数声明 */
void KeyScan();
void KeyDriver();
void KeyAction(unsigned char keycode);
/* 按键驱动函数，检测按键动作，调度相应动作函数，需在主循环中调用 */
void KeyDriver()
{
unsigned char i, j;
static unsigned char backup[4][4] = { //按键值备份，保存前一次的值
{1, 1, 1, 1}, {1, 1, 1, 1}, {1, 1, 1, 1}, {1, 1, 1, 1}
};
for (i=0; i<4; i ) //循环检测4*4的矩阵按键
{
for (j=0; j<4; j )
{
if (backup[i][j] != KeySta[i][j]) //检测按键动作
{
if (backup[i][j] != 0) //按键按下时执行动作
{
KeyAction(KeyCodeMap[i][j]); //调用按键动作函数
}
backup[i][j] = KeySta[i][j]; //刷新前一次的备份值
}
}
}
}
/* 按键扫描函数，需在定时中断中调用，推荐调用间隔1ms */
void KeyScan()
{
unsigned char i;
static unsigned char keyout = 0; //矩阵按键扫描输出索引
static unsigned char keybuf[4][4] = { //矩阵按键扫描缓冲区
{0xFF, 0xFF, 0xFF, 0xFF}, {0xFF, 0xFF, 0xFF, 0xFF},
{0xFF, 0xFF, 0xFF, 0xFF}, {0xFF, 0xFF, 0xFF, 0xFF}
};
//将一行的4个按键值移入缓冲区
keybuf[keyout][0] = (keybuf[keyout][0] << 1) | KEY_IN_1;
keybuf[keyout][1] = (keybuf[keyout][1] << 1) | KEY_IN_2;
keybuf[keyout][2] = (keybuf[keyout][2] << 1) | KEY_IN_3;
keybuf[keyout][3] = (keybuf[keyout][3] << 1) | KEY_IN_4;
//消抖后更新按键状态
for (i=0; i<4; i ) //每行4个按键，所以循环4次
{
if ((keybuf[keyout][i] & 0x0F) == 0x00)
{ //连续4次扫描值为0，即4*4ms内都是按下状态时，可认为按键已稳定的按下
KeySta[keyout][i] = 0;
}
else if ((keybuf[keyout][i] & 0x0F) == 0x0F)
{ //连续4次扫描值为1，即4*4ms内都是弹起状态时，可认为按键已稳定的弹起
KeySta[keyout][i] = 1;
}
}
//执行下一次的扫描输出
keyout ; //输出索引递增
keyout &= 0x03; //索引值加到4即归零
switch (keyout) //根据索引值，释放当前输出引脚，拉低下次的输出引脚
{
case 0: KEY_OUT_4 = 1; KEY_OUT_1 = 0; break;
case 1: KEY_OUT_1 = 1; KEY_OUT_2 = 0; break;
case 2: KEY_OUT_2 = 1; KEY_OUT_3 = 0; break;
case 3: KEY_OUT_3 = 1; KEY_OUT_4 = 0; break;
default: break;
}
}
void KeyAction(unsigned char keycode)
{
disBuf = keycode;
}
void delay(uint z) {
uint x, y;
for(x = z; x > 0; x--)
for(y = 110; y > 0; y--);
}
void write_com(uchar com) {
lcdrs = 0;
P0 = com;
delay(5);
lcden = 1;
delay(5);
lcden = 0;
}
void write_data(uchar date) {
lcdrs = 1;
P0 = date;
delay(5);
lcden = 1;
delay(5);
lcden = 0;
}
void init() {
rw = 0;
lcden = 0;
write_com(0x38);
write_com(0x0e);
write_com(0x06);
write_com(0x01);
}
void main() {
init();
write_com( 0x00 | 0x80 );
for(num = 0; num < 16; num ) {
write_data(table1[num]);
delay(100);
}
write_com( 0x40 | 0x80 );
for(num = 0; num < 16; num ) {
write_data(table2[num]);
delay(100);
}
write_com( 0x40 | 0x80 );
for(num = 0; num < 16; num ) {
write_data(table3[num]);
delay(100);
}
while(1)
{
KeyScan();
KeyDriver();
write_com( 0x40 | 0x80 );
write_data(disBuf);
}
}思考题
1. LCD 显示改为数码管显示(选做); 2. 若要实现数字键 0~9 按下后,直接在 LCD 上显示数字,如何修改程序?
