用keil写一个lcd1602按键切换屏幕，第一屏幕上显示“xingming”，第二屏幕上显示“xuehao”

第一个问题的代码如下：

#include <reg51.h>
#include <intrins.h>

#define LCD_DB P0
sbit LCD_RS = P2^0;
sbit LCD_RW = P2^1;
sbit LCD_EN = P2^2;

void delay_ms(unsigned int t)
{
    unsigned int i, j;
    for(i=0; i<t; i++)
        for(j=0; j<123; j++);
}

void lcd_write_command(unsigned char command)
{
    LCD_RS = 0;
    LCD_RW = 0;
    LCD_DB = command;
    LCD_EN = 1;
    _nop_();
    _nop_();
    LCD_EN = 0;
}

void lcd_write_data(unsigned char data)
{
    LCD_RS = 1;
    LCD_RW = 0;
    LCD_DB = data;
    LCD_EN = 1;
    _nop_();
    _nop_();
    LCD_EN = 0;
}

void lcd_init()
{
     lcd_write_command(0x38);  
     delay_ms(5);
     lcd_write_command(0x38); 
     delay_ms(5);
     lcd_write_command(0x38);  
     delay_ms(5);
     lcd_write_command(0x38); 
     delay_ms(5);
     lcd_write_command(0x08);  
     delay_ms(5);
     lcd_write_command(0x01); 
     delay_ms(5);
     lcd_write_command(0x06);  
     delay_ms(5);
     lcd_write_command(0x0c);  
     delay_ms(5);
}

void display_name()
{
    lcd_write_command(0x80);
    lcd_write_data('x');
    lcd_write_data('i');
    lcd_write_data('n');
    lcd_write_data('g');
    lcd_write_data('m');
    lcd_write_data('i');
    lcd_write_data('n');
    lcd_write_data('g');
}

void display_number()
{
    lcd_write_command(0x80);
    lcd_write_data('x');
    lcd_write_data('u');
    lcd_write_data('e');
    lcd_write_data('h');
    lcd_write_data('a');
    lcd_write_data('o');
}

void main()
{
    unsigned char key = 0;
    lcd_init();
    display_name();
    while(1)
    {
        key = P1;
        if(key == 0xfe) 
        {
            display_name();
        }
        if(key == 0xfd)
        {
            display_number();
        }
    }
}

在这个代码中，我通过 `P1` 来读取按键的值，如果按下了第一个按键，则显示“xingming”；如果按下了第二个按键，则显示“xuehao”。