51单片机利用e1的4*4矩阵键盘和a3区的lcd1602构成简单的按键输入系统，实现对矩阵键盘的扫描，并利用lcd1602显示按下的按键的号。16个按键的键号分别对应16个数值：0~15。的程序

好的，以下是51单片机利用e1的4*4矩阵键盘和a3区的lcd1602构成简单的按键输入系统，实现对矩阵键盘的扫描，并利用lcd1602显示按下的按键的号。16个按键的键号分别对应16个数值：0~15。的程序：

#include <reg51.h>

#define LCD1602_DB P0
sbit LCD1602_RS = P2^6;
sbit LCD1602_RW = P2^5;
sbit LCD1602_E  = P2^7;
sbit KBD_ROW0  = P1^0;
sbit KBD_ROW1  = P1^1;
sbit KBD_ROW2  = P1^2;
sbit KBD_ROW3  = P1^3;
sbit KBD_COL0  = P1^4;
sbit KBD_COL1  = P1^5;
sbit KBD_COL2  = P1^6;
sbit KBD_COL3  = P1^7;

void delay(unsigned int i)
{
    while(i--);
}

void write_lcd1602_cmd(unsigned char cmd)
{
    LCD1602_RS = 0;
    LCD1602_RW = 0;
    LCD1602_E = 1;
    LCD1602_DB = cmd;
    delay(100);
    LCD1602_E = 0;
}

void write_lcd1602_dat(unsigned char dat)
{
    LCD1602_RS = 1;
    LCD1602_RW = 0;
    LCD1602_E = 1;
    LCD1602_DB = dat;
    delay(100);
    LCD1602_E = 0;
}

void init_lcd1602()
{
    write_lcd1602_cmd(0x38);
    write_lcd1602_cmd(0x0c);
    write_lcd1602_cmd(0x06);
    write_lcd1602_cmd(0x01);
}

void kbd_scan()
{
    unsigned char key = 0xff;
    KBD_ROW0 = 0;
    KBD_ROW1 = 1;
    KBD_ROW2 = 1;
    KBD_ROW3 = 1;
    if(KBD_COL0 == 0) key = 0;
    if(KBD_COL1 == 0) key = 1;
    if(KBD_COL2 == 0) key = 2;
    if(KBD_COL3 == 0) key = 3;
    KBD_ROW0 = 1;
    KBD_ROW1 = 0;
    KBD_ROW2 = 1;
    KBD_ROW3 = 1;
    if(KBD_COL0 == 0) key = 4;
    if(KBD_COL1 == 0) key = 5;
    if(KBD_COL2 == 0) key = 6;
    if(KBD_COL3 == 0) key = 7;
    KBD_ROW0 = 1;
    KBD_ROW1 = 1;
    KBD_ROW2 = 0;
    KBD_ROW3 = 1;
    if(KBD_COL0 == 0) key = 8;
    if(KBD_COL1 == 0) key = 9;
    if(KBD_COL2 == 0) key = 10;
    if(KBD_COL3 == 0) key = 11;
    KBD_ROW0 = 1;
    KBD_ROW1 = 1;
    KBD_ROW2 = 1;
    KBD_ROW3 = 0;
    if(KBD_COL0 == 0) key = 12;
    if(KBD_COL1 == 0) key = 13;
    if(KBD_COL2 == 0) key = 14;
    if(KBD_COL3 == 0) key = 15;
    if(key != 0xff)
    {
        write_lcd1602_cmd(0x80);
        write_lcd1602_dat(key/10+'0');
        write_lcd1602_dat(key%10+'0');
    }
}

void main()
{
    init_lcd1602();
    while(1)
    {
        kbd_scan();
    }
}

这个程序的作用是对矩阵键盘进行扫描，并利用lcd1602显示按下的按键的号。程序首先对lcd1602进行初始化，然后进入一个无限循环，在循环里调用kbd_scan函数对矩阵键盘进行扫描，并将按下的按键的号码显示在lcd1602上。具体的矩阵键盘扫描过程在kbd_scan函数中实现。