#include  "reg51.h" 
#include  "math.h"
#include  "intrins.h"  
#define   uint      unsigned int 
#define   uchar     unsigned char   
#define   led_sec   P1 
#define   dac_adr   0x7fff     //初始DAC0832的地址 
sbit      inc_key = P3^0;      //"+" 鍵 
sbit      dec_key = P3^1;    //"-" 鍵 
sbit      step_key = P3^2; 	   //調整鍵 
sbit      ten = P3^3;          //數碼管的十位 
 
sbit      one = P3^4;  //數碼管的個位 
sbit      point  = P3^5;   	   //數碼管的小數位 
char xdata  dacreg  _at_  dac_adr;  //定義DAC0832的地址 
bit  flag0 = 0; 
uchar arry10[10] = { 0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90}; 
uchar arry1[10] = { 0x40,0x79,0x24,0x30,0x19,0x12,0x02,0x78,0x00,0x10}; 
uchar arry0[10] = { 0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90}; 
//顯示部分
uchar * ptr10 = arry10; 
uchar * ptr1 = arry1; 
uchar * ptr0 = arry0; 
void  ini_int(void) //中斷初始化 
{ 
  inc_key = 1; 
  dec_key = 1; 
  EA = 1; 
  EX0 = 1; 
  IT0 = 1;  //邊沿觸發方式        
} 
//**************************delayfunction************************************ 
//延時動態掃描 


void  delay( uint count)  //延遲周期是 20us 
{ uint i,j;
  for (i=0;i<count;i++);
  for (j=0;j<240;j++);
} 
//**************************buffer************************************** 
//根據地址查表得出要顯示的電壓值 
void buffer(uchar led10,uchar led1,uchar led0) //緩沖區
{ 
  ten = 0; 
  led_sec = *(led10 + ptr10);        
  delay(500);        // 延遲 10ms 
  ten = 1; 
  one = 0; 
  led_sec = *(led1 + ptr1); 
  delay(500);      // 延遲 10ms
  one = 1; 
  point = 0; 
  led_sec = *(led0 + ptr0); 
  delay(500);      // 延遲 10ms
  point = 1; 
} 

//BCD碼到十進制的轉換 
void disp_out(unsigned char dat) 
{   
  uchar dig_10,dig_1,dig_0,temp,temp1; 
  temp = dat; 
  dig_10 = temp/100; 
  temp1 = temp%100; 
  dig_1 = temp1/10; 
  dig_0 = temp%10; 
  buffer(dig_10,dig_1,dig_0); 
} 
//**********************主程序*********************************** 
void  main() 
{  
  unsigned char dac_dat,dac_temp; 
  uchar    inc_key_temp = 1; 
  uchar    dec_key_temp = 1; 
  dac_dat = 0xd; 
  flag0 = 0;            // 初始化標志位 
  dac_temp = dac_dat; 
  dacreg = dac_temp;    //把輸出電位至到 1.3V 
  ini_int();          //外部中斷 
  disp_out(dac_temp); 
  while (1) //*~dec_key | ~inc_key*/
  {  
 
    if ( inc_key == 0 ) //判斷有沒有加鍵按下
      { 
        delay(600); 
        inc_key_temp = (inc_key == 0) ? 0 : 1; 
//按鍵釋放前一直掃描顯示,如果按鍵釋放則跳出并 "+" 1 
       do 
          { 
            disp_out(dac_temp); 
          } 
        while (inc_key == 0); 
 



      } 
    else if( dec_key == 0 ) //判斷有沒有減鍵按下
      {  
        delay(600); 
        dec_key_temp = (dec_key == 0) ? 0 : 1; //按鍵釋放前一直掃描顯示,如果按鍵釋放則跳出并 "-" 1 
        do 
          { 
            disp_out(dac_temp); 
          } 
        while (dec_key == 0); 
      } 
    else  
      { 
         ; 
      } 
         if ( ~flag0 & ~dec_key_temp & (dac_temp>13))       //步進減 0.1V
         {  
            dec_key_temp = 1; 
            dac_dat = dac_dat - 1; 
            dac_temp = dac_dat; 
            dacreg = dac_temp; 
            disp_out(dac_temp); 
         } 
         else if ( ~flag0 & ~inc_key_temp & (dac_dat<161)) // 步進加 0.1V 
         { 
            inc_key_temp = 1; 
            dac_dat = dac_dat + 1; 
    dac_temp = dac_dat; 
            dacreg = dac_temp; 
            disp_out(dac_temp); 
         } 
         else if ( flag0 & ~dec_key_temp & (dac_dat>23))  //步進減 1V 
         {   
    dec_key_temp = 1; 
            dac_dat = dac_dat - 10; 
    dac_temp = dac_dat; 
            dacreg = dac_temp; 
            disp_out(dac_temp); 
         } 
         else if (flag0 & ~inc_key_temp & (dac_dat<151))   // 步進加 1V 
         { 
            inc_key_temp = 1; 
    dac_dat = dac_dat + 10; 
    dac_temp = dac_dat; 
            dacreg = dac_temp; 
            disp_out(dac_temp); 
         } 
         else  
         { 
            disp_out(dac_temp); 
         } 
  }  


} 
//*************************中斷************************** 
void int0(void) interrupt 0 using 1
{ 
  flag0 = ~flag0; 
}