本程序是矩阵按键扫描，数码管动态扫描，定时器中断的综合练习，其中秒表显示计数函数用了2种写法，是2种不同的思路。
代码已经在KST-51 v1.3.2开发板验证通过。
#include <reg52.h>
sbit ADDR0 = P1^0;
sbit ADDR1 = P1^1;
sbit ADDR2 = P1^1;
sbit ADDR3 = P1^3;
sbit ENLED = P1^4;
sbit keyIn1 = P2^4;
sbit keyIn2 = P2^5;
sbit keyIn3 = P2^6;
sbit keyIn4 = P2^7;
sbit keyOut1 = P2^3;
sbit keyOut2 = P2^2;
sbit keyOut3 = P2^1;
sbit keyOut4 = P2^0;
//数码管显示字符转换表
unsigned char code ledChar[16] = {
0xC0, 0xF9, 0xA4, 0xB0, 0x99, 0x92, 0x82, 0xF8,
0x80, 0x90, 0x88, 0x83, 0xC6, 0xA1, 0x86, 0x8E
};
//数码管显示缓冲区
unsigned char ledBuff[6] = {
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF
};
//矩阵按键真值表
unsigned char code keyCodeMap[4][4] = {
{ 0x31, 0x32, 0x33, 0x26 }, //数字键1、数字键2、数字键3、向上键
{ 0x34, 0x35, 0x36, 0x25 }, //数字键4、数字键5、数字键6、向左键
{ 0x37, 0x38, 0x39, 0x28 }, //数字键7、数字键8、数字键9、向下键
{ 0x30, 0x1B, 0x0D, 0x27 } //数字键0、ESC键、 回车键、 向右键
};
//按键当前状态
unsigned char keySta[4][4] = {
{1, 1, 1, 1}, {1, 1, 1, 1}, {1, 1, 1, 1}, {1, 1, 1, 1}
};
unsigned char T0RH = 0; //Timer0重载值的高字节（高8位）
unsigned char T0RL = 0; //Timer0重载值的低字节（低8位）
bit stopWatchRunning = 0; //秒表运行标志位
bit stopWatchRefresh = 1; //秒表刷新标志位
unsigned int integerPart = 0; //秒表的整数部分
unsigned char decimalPart = 0; //表秒的小数部分
void ConfigTimer0(unsigned int ms);
void StopWatchDisplay();
void KeyDriver();
void main()
{
EA = 1; //使能总中断
ENLED = 0; //选择数码管进行显示
ADDR3 = 1;
ConfigTimer0(2); //配置Timer0，定时2ms
while (1)
{
if (stopWatchRefresh) //秒表数刷新
{
stopWatchRefresh = 0;
StopWatchDisplay(); //显示当前的秒表数值
}
KeyDriver(); //按键驱动函数
}
}
//配置并启动Timer0，ms为Timer0的定时时间，单位毫秒
void ConfigTimer0(unsigned int ms)
{
unsigned long reload; //临时变量
reload = 11059200 / 12; //定时器的计数频率
reload = (reload * ms) / 1000; //计算所需的计数值，也就是溢出值
reload = 65536 - reload + 18; //计算定时器的重载值，也就是初值，并且补偿中断响应误差
T0RH = (unsigned char)(reload >> 8);//定时器重载值拆分为高低字节
T0RL = (unsigned char)reload;
TMOD &= 0xF0; //清零Timer0的控制位
TMOD |= 0x01; //配置Timer0为模式1
TH0 = T0RH; //加载Timer0的重载值
TL0 = T0RL;
ET0 = 1; //使能Timer0中断
TR0 = 1; //启动Timer0
}
/*
//秒表计数显示函数
void StopWatchDisplay()
{
signed char i;
unsigned char buff[4];
//将小数部分分离，并给数码管缓冲区赋值
ledBuff[0] = ledChar[decimalPart % 10];
ledBuff[1] = ledChar[decimalPart / 10 % 10];
//将整数部分分离
buff[0] = integerPart % 10;
buff[1] = integerPart / 10 % 10;
buff[2] = integerPart / 100 % 10;
buff[3] = integerPart / 1000 % 10;
//整数部分高位为零不显示
for (i = 3; i >= 1; i--)
{
if (buff[i] == 0)
{
ledBuff[i + 2] = 0xFF;
}
else
{
break;
}
}
for ( ; i >= 0; i--)
{
ledBuff[i + 2] = ledChar[buff[i]];
}
//点亮小数点
ledBuff[2] &= 0x7F;
}
*/
//秒表计数显示函数
void StopWatchDisplay()
{
signed char i;
static unsigned char buff[6];
static unsigned int temp;
temp = integerPart; //将整数部分赋给静态变量temp
buff[0] = decimalPart % 10; //分离小数部分，并赋值给数值缓冲区
buff[1] = decimalPart / 10 % 10;
for (i = 2; i <= 5; i++) //循环分离整数部分，并赋值给数值缓冲区
{
buff[i] = temp % 10;
temp /= 10;
}
for (i = 5; i >= 3; i--) //数码管的高位遇到0不显示（小数部分和整数部分的最低位是必须显示的）
{
if (buff[i] == 0)
{
ledBuff[i] = 0xFF;
}
else{
break;
}
}
for ( ; i >= 0; i--)
{
ledBuff[i] = ledChar[buff[i]];
}
ledBuff[2] &= 0x7F; //点亮数码管小数点
}
//按键动作函数
void KeyAction(unsigned char keyCode)
{
if (keyCode == 0x0D) //按下回车键
{
if (stopWatchRunning) //如果秒表是运行状态
{
stopWatchRunning = 0; //让秒表停止状态
}
else if (stopWatchRunning == 0) //如果秒表是停止状态
{
stopWatchRunning = 1; //让秒表运行状态
}
}
else if (keyCode == 0x1B) //按下ESC键
{
stopWatchRunning = 0; //秒表停止
integerPart = 0; //秒表整数部分清零
decimalPart = 0; //秒表小数部分清零
stopWatchRefresh = 1; //秒表刷新
}
}
//按键驱动函数
void KeyDriver()
{
unsigned char i, j;
static unsigned char keyBackup[4][4] = { //按键备份值，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 (keySta[i][j] != keyBackup[i][j]) //检测当前按键值和备份值不一致，说明按键有动作了
{
if (keySta[i][j] == 0) //如果当前按键是按下的状态
{
KeyAction(keyCodeMap[i][j]); //调用动作函数
}
keyBackup[i][j] = keySta[i][j]; //备份一次当前的按键值
}
}
}
}
//数码管扫描函数
void LedScan()
{
static unsigned char i = 0;
P0 = 0xFF; //关闭所有段选位，消隐
P1 = (P1 & 0xF8) | i; //位选索引赋值到P1口的低3位
P0 = ledBuff[i]; //缓冲区索引位置的数据送到P0口，
if (i < 5) //索引递增循环，遍历整个缓冲区
{
i++;
}
else{
i = 0;
}
}
//按键扫描函数
void KeyScan()
{
unsigned char i;
static unsigned keyout = 0;
//按键扫描缓冲区
static unsigned char keyBuff[4][4] = {
{0xFF, 0xFF, 0xFF, 0xFF}, {0xFF, 0xFF, 0xFF, 0xFF},
{0xFF, 0xFF, 0xFF, 0xFF}, {0xFF, 0xFF, 0xFF, 0xFF}
};
//按键值一位一位的移入缓冲区
keyBuff[keyout][0] = (keyBuff[keyout][0] << 1) | keyIn1;
keyBuff[keyout][1] = (keyBuff[keyout][1] << 1) | keyIn2;
keyBuff[keyout][2] = (keyBuff[keyout][2] << 1) | keyIn3;
keyBuff[keyout][3] = (keyBuff[keyout][3] << 1) | keyIn4;
//每行4个按键，所以循环4次
for (i = 0; i < 4; i++)
{
if ((keyBuff[keyout][i] & 0x0F) == 0x00) //连续4次扫描值为0，即2ms * 4 * 4 = 32ms内都是按下状态
{
keySta[keyout][i] = 0;
}
else if ((keyBuff[keyout][i] & 0x0F) == 0x0F) //连续4次扫描值为1，即2ms * 4 * 4 = 32ms内都是按下状态
{
keySta[keyout][i] = 1;
}
}
keyout++; //输出索引递增
keyout &= 0x03; //输出索引加到4即归零
switch (keyout) //根据索引，释放当前的输出引脚，拉低下次的输出引脚
{
case 0: keyOut4 = 1; keyOut1 = 0; break;
case 1: keyOut1 = 1; keyOut2 = 0; break;
case 2: keyOut2 = 1; keyOut3 = 0; break;
case 3: keyOut3 = 1; keyOut4 = 0; break;
default: break;
}
}
//秒表计数函数，每10ms调用一次秒表计数累加
void StopWatchCount()
{
if (stopWatchRunning) //秒表处于运行状态
{
decimalPart++; //小数部分+1
if (decimalPart >= 100) //小数部分加到100时进位到整数部分
{
decimalPart = 0; //小数部分清零
integerPart++; //整数部分+1
if (integerPart >= 10000) //整数部分加到10000时归零
{
integerPart = 0;
}
}
stopWatchRefresh = 1; //秒表刷新
}
}
void InterruptTimer0() interrupt 1
{
static unsigned int tmr10ms = 0;
TH0 = T0RH; //重新加载重载值
TL0 = T0RL;
LedScan(); //数码管刷新
KeyScan(); //矩阵按键刷新
//定时10ms进行一次秒表计数
tmr10ms++;
if (tmr10ms >= 5)
{
tmr10ms = 0;
StopWatchCount();
}
}