#include <AT89X51.H>
#include<absacc.h>
#include<intrins.h>
#include<math.h>
#include <stdio.h>
 

sbit AD7705_DATA=P2^6;       // AD7705 input & output data
sbit AD7705_CLK=P2^7;        // AD7705 CLK

sbit AD7705_DRDY=P2^5;       // AD7705 data ready
sbit AD7705_CS  =P2^4;       // AD7705 CS
sbit AD7705_RESET  =P2^3;


unsigned char Counter,dis_index,dis_digit;
unsigned int T_Voltage;
unsigned char MSB_Data,LSB_Data,temp0,temp1,temp2,temp3,temp4,temp5;

unsigned char code Display_code[11]=
//{0xa0,0xF9,0xc4,0xd0,0x99,0x92,0x82,0xF8,0x80,0x90,0xFF,};
{0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90,0xFF};

void Delayms(unsigned char ms);
void AD7705_Start();
void AD7705_Read ();
void AD7705_Write_Reg(unsigned char Data_byte);
unsigned char AD7705_Read_Reg();
extern void SerialInit(void);

main()
{
 TMOD = 0x11;
 IT0 = 1;
 PCON=0X00;
 ET0 = 1;
 TH1 = 0xFC;
 TL1 = 0x17;
    TR0 = 1;
        
 EA = 1; 
 P0 = 0xff; P1 = 0xff; P2 = 0xff; P3 = 0xff;
 dis_digit = 0x77;
 dis_index = 0;
 Counter  = 0;
 AD7705_Start();
 while(1)
 {
 while(AD7705_DRDY);
   AD7705_Read();
   Delayms(50);
 }
}

void Delayms(unsigned char ms) 
// relay ms
{ unsigned char i;
 while(ms--)
 {
  for(i = 0; i < 120; i++);
 }
}

void AD7705_Start()
{
 AD7705_Write_Reg(0x20);
 AD7705_Write_Reg(0x0c);
 AD7705_Write_Reg(0x10);
 AD7705_Write_Reg(0x44);
}
/*****************************************/
void AD7705_Read()
{
 AD7705_Write_Reg(0x38);
 MSB_Data = AD7705_Read_Reg();
 LSB_Data = AD7705_Read_Reg();
 T_Voltage =(unsigned int)MSB_Data;
 T_Voltage = T_Voltage<<8;
 T_Voltage = T_Voltage | (unsigned int)LSB_Data;

 temp0 = T_Voltage/100000;
 temp1 = ((T_Voltage-temp0*100000)/10000);
 temp2 = ((T_Voltage-temp0*100000-temp1*10000)/1000);
 temp3 = ((T_Voltage-temp0*100000-temp1*10000-temp2*1000)/100);
 temp4 = (T_Voltage-temp0*100000-temp1*10000-temp2*1000-temp3*100)/10;
 temp5 = (T_Voltage-temp0*100000-temp1*10000-temp2*1000-temp3*100-temp4*10);

}
/*******************************************/

void AD7705_Write_Reg(unsigned char Data_byte)
{ 
 unsigned char i;
 AD7705_CS = 0;
 AD7705_CLK = 1;
        _nop_();
  _nop_();
 for(i = 0; i < 8; i++) 
 {
     AD7705_DATA = (bit)(Data_byte & 0x80);
  AD7705_CLK = 0;
        _nop_();
  _nop_();
  _nop_();
  AD7705_CLK = 1;
       
     Data_byte <<= 1;
 }
  _nop_();
  AD7705_CS = 1;
}
unsigned char AD7705_Read_Reg()
{ 
 unsigned char i,Data_read;
 AD7705_CS = 0;
 AD7705_CLK = 1;
     _nop_();
 for(i = 0; i < 8; i++) 
 {
     AD7705_CLK = 0;
        _nop_();
     _nop_();
  Data_read <<= 1;
  Data_read |= (unsigned char)AD7705_DATA;
  _nop_();
  _nop_();
        AD7705_CLK = 1;
        _nop_();
     _nop_();
 }
   _nop_();
  AD7705_CS = 1;
  AD7705_DRDY = 1;
  return(Data_read);
}

void time0(void) interrupt 1
{
 TR0 = 0;
 P2 = dis_digit;   //P2.7 --DS8
 P0 = Display_code[dis_index]; 
    
 TH0 = 0xFC;
 TL0 = 0x17;
 Counter++;
 if(Counter==1)
 {
 dis_digit = 0x77;
  dis_index = temp5;
    }else if(Counter==2)
 {
 dis_digit = 0xb7;
  dis_index = temp4;
 }else if(Counter==3)
 {
 dis_digit = 0xd7;
  dis_index = temp3;
 }else if(Counter==4)
 {
 dis_digit = 0xe7;
  dis_index = temp2;
 Counter = 0;
 }
 
    TR0 = 1;
}