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#include <reg52.h>
sbit ADDR3 = P1^3;
sbit ENLED = P1^4;
unsigned char code LedChar[] = { //数码管显示字符转换表
0xC0, 0xF9, 0xA4, 0xB0, 0x99, 0x92, 0x82, 0xF8,
0x80, 0x90, 0x88, 0x83, 0xC6, 0xA1, 0x86, 0x8E
};
unsigned char LedBuff[7] = { //数码管+独立LED显示缓冲区
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF
};
bit flag1s = 1; //1秒定时标志
unsigned char T0RH = 0; //T0重载值的高字节
unsigned char T0RL = 0; //T0重载值的低字节
void ConfigTimer0(unsigned int ms);
void TrafficLight();
void main()
{
EA = 1; //开总中断
ENLED = 0; //使能数码管和LED
ADDR3 = 1;
ConfigTimer0(1); //配置T0定时1ms
while (1)
{
if (flag1s) //每秒执行一次交通灯刷新
{
flag1s = 0;
TrafficLight();
}
}
}
/* 配置并启动T0，ms-T0定时时间 */
void ConfigTimer0(unsigned int ms)
{
unsigned long tmp; //临时变量
tmp = 11059200 / 12; //定时器计数频率
tmp = (tmp * ms) / 1000; //计算所需的计数值
tmp = 65536 - tmp; //计算定时器重载值
tmp = tmp + 13; //补偿中断响应延时造成的误差
T0RH = (unsigned char)(tmp>>8); //定时器重载值拆分为高低字节
T0RL = (unsigned char)tmp;
TMOD &= 0xF0; //清零T0的控制位
TMOD |= 0x01; //配置T0为模式1
TH0 = T0RH; //加载T0重载值
TL0 = T0RL;
ET0 = 1; //使能T0中断
TR0 = 1; //启动T0
}
/* 交通灯显示刷新函数 */
void TrafficLight()
{
static unsigned char color = 2; //颜色索引：0-绿色/1-黄色/2-红色
static unsigned char timer = 0; //倒计时定时器
if (timer == 0) //倒计时到0时，切换交通灯
{
switch (color) //LED8/9代表绿灯，LED5/6代表黄灯，LED2/3代表红灯
{
case 0: //切换到黄色，亮3秒
color = 1;
timer = 2;
LedBuff[6] = 0xE7;
break;
case 1: //切换到红色，亮30秒
color = 2;
timer = 29;
LedBuff[6] = 0xFC;
break;
case 2: //切换到绿色，亮40秒
color = 0;
timer = 39;
LedBuff[6] = 0x3F;
break;
default:
break;
}
}
else //倒计时未到0时，递减其计数值
{
timer--;
}
LedBuff[0] = LedChar[timer%10]; //倒计时数值个位显示
LedBuff[1] = LedChar[timer/10]; //倒计时数值十位显示
}
/* LED动态扫描刷新函数，需在定时中断中调用 */
void LedScan()
{
static unsigned char i = 0;
P0 = 0xFF;
P1 = (P1 & 0xF8) | i;
P0 = LedBuff[i];
if (i < 6)
i++;
else
i = 0;
}
/* T0中断服务函数，完成LED扫描和秒定时 */
void InterruptTimer0() interrupt 1
{
static unsigned int tmr1s = 0;
TH0 = T0RH;
TL0 = T0RL;
LedScan();
tmr1s++;
if (tmr1s >= 1000)
{
tmr1s = 0;
flag1s = 1;
}
}
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