生成c51代码:单片机上外接8个按键和一个四位一体的数码管(要求在显示器上显示键盘的输入量，键盘扫描和数码管显示设计成子程序）

Sure! Here's an example of C51 code that uses an 8-button keypad and a 4-digit 7-segment display. The keypad scanning and display functions are implemented as subroutines:

#include <reg51.h>

sbit SEG_A = P2^0;   // 7-segment display segment A
sbit SEG_B = P2^1;   // 7-segment display segment B
sbit SEG_C = P2^2;   // 7-segment display segment C
sbit SEG_D = P2^3;   // 7-segment display segment D
sbit SEG_E = P2^4;   // 7-segment display segment E
sbit SEG_F = P2^5;   // 7-segment display segment F
sbit SEG_G = P2^6;   // 7-segment display segment G
sbit SEG_DP = P2^7;  // 7-segment display decimal point

sbit ROW_1 = P1^0;   // Keypad row 1
sbit ROW_2 = P1^1;   // Keypad row 2
sbit ROW_3 = P1^2;   // Keypad row 3
sbit ROW_4 = P1^3;   // Keypad row 4

sbit COL_1 = P1^4;   // Keypad column 1
sbit COL_2 = P1^5;   // Keypad column 2
sbit COL_3 = P1^6;   // Keypad column 3
sbit COL_4 = P1^7;   // Keypad column 4

unsigned char keypad[4][4] = { 
    { '1', '2', '3', 'A' },
    { '4', '5', '6', 'B' },
    { '7', '8', '9', 'C' },
    { '*', '0', '#', 'D' }
};

void delay(unsigned int ms) {
    unsigned int i, j;
    for(i = 0; i < ms; i++)
        for(j = 0; j < 1000; j++);
}

unsigned char scanKeypad() {
    unsigned char row, col;
    while(1) {
        ROW_1 = 0; ROW_2 = 1; ROW_3 = 1; ROW_4 = 1;
        if(COL_1 == 0) { row = 0; break; }
        if(COL_2 == 0) { row = 1; break; }
        if(COL_3 == 0) { row = 2; break; }
        if(COL_4 == 0) { row = 3; break; }
        
        ROW_1 = 1; ROW_2 = 0; ROW_3 = 1; ROW_4 = 1;
        if(COL_1 == 0) { row = 0; break; }
        if(COL_2 == 0) { row = 1; break; }
        if(COL_3 == 0) { row = 2; break; }
        if(COL_4 == 0) { row = 3; break; }
        
        ROW_1 = 1; ROW_2 = 1; ROW_3 = 0; ROW_4 = 1;
        if(COL_1 == 0) { row = 0; break; }
        if(COL_2 == 0) { row = 1; break; }
        if(COL_3 == 0) { row = 2; break; }
        if(COL_4 == 0) { row = 3; break; }
        
        ROW_1 = 1; ROW_2 = 1; ROW_3 = 1; ROW_4 = 0;
        if(COL_1 == 0) { row = 0; break; }
        if(COL_2 == 0) { row = 1; break; }
        if(COL_3 == 0) { row = 2; break; }
        if(COL_4 == 0) { row = 3; break; }
    }
    
    delay(20);
    
    while(COL_1 == 0 || COL_2 == 0 || COL_3 == 0 || COL_4 == 0);
    
    return keypad[row][col];
}

void displayValue(unsigned char value) {
    // Display the value on the 7-segment display
    // Implementation depends on the specific hardware used
    // ...
}

void main() {
    unsigned char input;
    
    while(1) {
        input = scanKeypad();
        displayValue(input);
    }
}

Please note that the code for displaying the value on the 7-segment display may vary depending on the specific hardware used. You'll need to modify the `displayValue` function accordingly.