基于AT89s52单片机的计数器并用数码管显示

以下是基于AT89s52单片机的计数器并用数码管显示的程序：

#include <REG52.h>

#define uchar unsigned char
#define uint unsigned int

sbit D1 = P2^0;
sbit D2 = P2^1;
sbit D3 = P2^2;
sbit D4 = P2^3;
sbit EN = P2^4;
sbit RS = P2^5;

uint count = 0;

void delay(uint xms) {
    uint i, j;
    for (i = xms; i > 0; i--)
        for (j = 110; j > 0; j--);
}

void write_command(uchar command) {
    RS = 0;
    P0 = command;
    EN = 1;
    delay(1);
    EN = 0;
}

void write_data(uchar data) {
    RS = 1;
    P0 = data;
    EN = 1;
    delay(1);
    EN = 0;
}

void init_lcd() {
    write_command(0x38);
    write_command(0x0c);
    write_command(0x06);
    write_command(0x01);
}

void display_count() {
    uint i, j, k, l;
    uchar a, b, c, d;

    a = count % 10;
    b = count / 10 % 10;
    c = count / 100 % 10;
    d = count / 1000 % 10;

    for (i = 0; i < 50; i++) {
        for (j = 0; j < 4; j++) {
            switch (j) {
                case 0: P1 = 0x00; break;
                case 1: P1 = 0x10; break;
                case 2: P1 = 0x20; break;
                case 3: P1 = 0x30; break;
            }

            switch (j) {
                case 0: k = a; break;
                case 1: k = b; break;
                case 2: k = c; break;
                case 3: k = d; break;
            }

            switch (k) {
                case 0: P0 = 0x3f; break;
                case 1: P0 = 0x06; break;
                case 2: P0 = 0x5b; break;
                case 3: P0 = 0x4f; break;
                case 4: P0 = 0x66; break;
                case 5: P0 = 0x6d; break;
                case 6: P0 = 0x7d; break;
                case 7: P0 = 0x07; break;
                case 8: P0 = 0x7f; break;
                case 9: P0 = 0x6f; break;
            }

            switch (j) {
                case 0: D1 = 1; break;
                case 1: D2 = 1; break;
                case 2: D3 = 1; break;
                case 3: D4 = 1; break;
            }

            delay(1);

            switch (j) {
                case 0: D1 = 0; break;
                case 1: D2 = 0; break;
                case 2: D3 = 0; break;
                case 3: D4 = 0; break;
            }
        }
    }
}

void main() {
    init_lcd();

    while (1) {
        display_count();
        count++;
    }
}

在程序中定义了四个数码管显示位的引脚，分别是P2.0-P2.3。定义了使能引脚EN和RS引脚，分别用于写入指令和数据。在程序中定义了计数器count，并在display_count()函数中将count拆分为四个数码管位需要显示的数字，然后通过循环一位一位地显示。在循环中，首先通过P1口控制数码管位选，然后根据需要显示的数字选择数码管段选，最后通过D1-D4控制数码管的点亮。程序中使用了延时函数delay()来控制数码管的刷新频率。在主函数中，通过不断调用display_count()函数实现计数器的自增并用数码管显示。