AT89C51单片机数字时钟是设计代码

以下是一个使用AT89C51单片机编写的数字时钟示例代码：

#include <reg51.h>

// 定义DS1302的IO口
sbit DS1302_RST = P1^0;
sbit DS1302_DAT = P1^1;
sbit DS1302_CLK = P1^2;

// 定义七段数码管的IO口
sbit LED_A = P2^0;
sbit LED_B = P2^1;
sbit LED_C = P2^2;
sbit LED_D = P2^3;
sbit LED_E = P2^4;
sbit LED_F = P2^5;
sbit LED_G = P2^6;
sbit LED_DP = P2^7;

// 定义数字对应的七段LED灯状态
unsigned char num_led[10][8] = {
  {0x3f},  // 0
  {0x06},  // 1
  {0x5b},  // 2
  {0x4f},  // 3
  {0x66},  // 4
  {0x6d},  // 5
  {0x7d},  // 6
  {0x07},  // 7
  {0x7f},  // 8
  {0x6f}   // 9
};

// 初始化DS1302时钟
void ds1302_init() {
  DS1302_RST = 1;
  DS1302_CLK = 0;
  DS1302_RST = 0;
  DS1302_DAT = 0;
  DS1302_CLK = 1;
  DS1302_RST = 1;
}

// 向DS1302时钟写入一个字节数据
void ds1302_write_byte(unsigned char dat) {
  unsigned char i;
  for (i = 0; i < 8; i++) {
    DS1302_DAT = dat & 0x01;
    dat >>= 1;
    DS1302_CLK = 0;
    DS1302_CLK = 1;
  }
}

// 从DS1302时钟读取一个字节数据
unsigned char ds1302_read_byte() {
  unsigned char i, dat = 0;
  for (i = 0; i < 8; i++) {
    dat >>= 1;
    if (DS1302_DAT) {
      dat |= 0x80;
    }
    DS1302_CLK = 0;
    DS1302_CLK = 1;
  }
  return dat;
}

// 设置DS1302时钟的时间
void ds1302_set_time(unsigned char hour, unsigned char minute, unsigned char second) {
  ds1302_init();
  ds1302_write_byte(0x8e);
  ds1302_write_byte(0);
  ds1302_write_byte(hour);
  ds1302_write_byte(minute);
  ds1302_write_byte(second);
  ds1302_write_byte(0);
  ds1302_write_byte(0);
  ds1302_write_byte(0);
  ds1302_write_byte(0);
  ds1302_write_byte(0);
  ds1302_write_byte(0);
  ds1302_write_byte(0);
  ds1302_write_byte(0);
  ds1302_write_byte(0);
  ds1302_write_byte(0);
  ds1302_write_byte(0);
  ds1302_write_byte(0);
  ds1302_write_byte(0x80);
}

// 从DS1302时钟读取时间
void ds1302_get_time(unsigned char *hour, unsigned char *minute, unsigned char *second) {
  unsigned char dat;
  ds1302_init();
  ds1302_write_byte(0xbe);
  dat = ds1302_read_byte();
  *second = (dat & 0x0f) + ((dat >> 4) * 10);
  dat = ds1302_read_byte();
  *minute = (dat & 0x0f) + ((dat >> 4) * 10);
  dat = ds1302_read_byte();
  *hour = (dat & 0x0f) + ((dat >> 4) * 10);
}

// 根据数字显示相应的七段LED灯状态
void display_num(unsigned char num, unsigned char pos) {
  unsigned char *leds = num_led[num];

  LED_A = leds[0];
  LED_B = leds[1];
  LED_C = leds[2];
  LED_D = leds[3];
  LED_E = leds[4];
  LED_F = leds[5];
  LED_G = leds[6];
  LED_DP = leds[7];

  // 设置位选信号，让对应的数码管显示
  switch (pos) {
    case 0:
      P0 = 0x01;
      break;
    case 1:
      P0 = 0x02;
      break;
    case 2:
      P0 = 0x04;
      break;
    case 3:
      P0 = 0x08;
      break;
    case 4:
      P0 = 0x10;
      break;
    case 5:
      P0 = 0x20;
      break;
  }
}

void main() {
  unsigned char hour, minute, second;
  ds1302_set_time(12, 0, 0);  // 设置时钟初始时间

  while (1) {
    ds1302_get_time(&hour, &minute, &second);  // 读取时钟时间
    display_num(hour / 10, 0);
    display_num(hour % 10, 1);
    display_num(minute / 10, 2);
    display_num(minute % 10, 3);
    display_num(second / 10, 4);
    display_num(second % 10, 5);
  }
}

该代码使用了AT89C51单片机、DS1302时钟芯片和七段LED灯，实现了数字时钟的显示功能。在`ds1302_init()`函数中初始化了时钟的IO口，在`ds1302_set_time()`和`ds1302_get_time()`函数中实现了对时钟的写入和读取操作。`display_num()`函数用于根据数字显示相应的LED灯状态，并通过设置位选信号让对应的数码管显示。在`main()`函数中循环读取时钟时间并显示到LED灯上。