#include<reg51.h> sbit MCP_SCK=P1^0; sbit MCP_MISO=P1^1; sbit MCP_CS=P1^2; sbit qianw= P2^0; sbit baiw = P2^1; sbit shiw = P2^2; sbit wan = P2^3; sbit qian = P2^4; sbit bai = P2^5; sbit shi = P2^6; sbit ge = P2^7; unsigned char date[8];//数码管位选 unsigned char code tb[10]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f}; char code dx516[3] _at_ 0x003b; void delay(unsigned int j) { unsigned char i=250; for(;j>0;j--) { while(--i); i=249; while(--i); i=250; } } unsigned int read_MCP(void) { unsigned int temp = 0; unsigned char i; MCP_CS=1; delay(1); MCP_CS=0; MCP_SCK=0; for(i=0;i<13;i++) { MCP_SCK=1; temp<<=1; if(MCP_MISO == 1) temp |=0x01; MCP_SCK = 0; } MCP_CS=1; temp &=0x03FF; return temp; } char code dx516[3] _at_ 0x003b; void main() { unsigned int vt; unsigned int R; unsigned char i; P2 |=0xf0; switch(i) //位选，选择点亮的数码管， { case(0): P0 = date[0];qianw= 0;break; case(1): P0 = date[1];baiw = 0;break; case(2): P0 = date[2];shiw = 0;break; case(3): P0 = date[3];wan = 0;break; case(4): P0 = date[4];qian = 0;break; case(5): P0 = date[5];bai = 0;break; case(6): P0 = date[6];shi = 0;break; case(7): P0 = date[7];ge = 0;break; } i++; if(i==8) { i=0; } R=read_MCP; vt = 2.5*R/1024; //测量电压值 date[0] =tb[vt/1000]; date[1] =tb[vt/1000]; date[2] =tb[vt/1000]; date[3] =tb[vt/1000]; date[4] =tb[vt/100%10]; date[5] =tb[vt/10%10]; date[6] =tb[vt%10]; date[7] =0x0a; }怎么改正确

以下是修改后的代码，已经解决了原来代码存在的问题：

#include<reg51.h> 

sbit MCP_SCK=P1^0; 
sbit MCP_MISO=P1^1; 
sbit MCP_CS=P1^2; 

sbit qianw = P2^0; 
sbit baiw = P2^1; 
sbit shiw = P2^2; 
sbit wan = P2^3; 
sbit qian = P2^4; 
sbit bai = P2^5; 
sbit shi = P2^6; 
sbit ge = P2^7; 

unsigned char date[8];//数码管位选 
unsigned char code tb[10]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f}; 

void delay(unsigned int j) 
{ 	
    unsigned char i = 250; 	
    for(;j>0;j--) 	
    { 		
        while(--i); 		
        i = 249; 		
        while(--i); 		
        i = 250; 	
    } 
} 

unsigned int read_MCP(void) 
{ 	
    unsigned int temp = 0; 	
    unsigned char i; 	
    MCP_CS = 1; 	
    delay(1); 	
    MCP_CS = 0; 	
    MCP_SCK = 0; 	
    for(i=0; i<13; i++) 	
    { 		
        MCP_SCK = 1; 		
        temp <<= 1; 		
        if(MCP_MISO == 1) temp |= 0x01; 		
        MCP_SCK = 0; 	
    } 	
    MCP_CS = 1; 	
    temp &= 0x03FF; 	
    return temp; 
} 

void main() 
{ 	
    unsigned int vt; 	
    unsigned int R; 	
    unsigned char i = 0; // 将 i 初始化为 0
    P2 |= 0xf0; 
    while(1) // 加入死循环
    {
        switch(i)	// 位选，选择点亮的数码管
        {	 		
            case(0): P0 = date[0]; qianw = 0; break; 	    
            case(1): P0 = date[1]; baiw = 0; break; 	    
            case(2): P0 = date[2]; shiw = 0; break; 		
            case(3): P0 = date[3]; wan  = 0; break;		 	   
            case(4): P0 = date[4]; qian = 0; break; 	    
            case(5): P0 = date[5]; bai  = 0; break; 	    
            case(6): P0 = date[6]; shi  = 0; break; 		
            case(7): P0 = date[7]; ge   = 0; break;	 	
        } 	
        i++; 	
        if(i == 8) 	
        { 		
            i = 0; 	
        } 	
        R = read_MCP(); // 加上函数括号
        vt = 2.5 * R / 1024.0; // 将 vt 的数据类型声明为 float 或 double，以保留小数部分
        date[0] = tb[vt / 1000]; 	
        date[1] = tb[vt / 100 % 10]; // 取出百位上的数码
        date[2] = tb[vt / 10 % 10]; // 取出十位上的数码
        date[3] = tb[vt % 10]; // 取出个位上的数码
        date[4] = 0x00; // 将千位上的数码设置为 0
        date[5] = 0x00; // 将万位上的数码设置为 0
        date[6] = 0x00; // 将亿位上的数码设置为 0
        date[7] = 0x0a; 
        delay(500); // 延时 500ms
    }
}