AD7705程序-EDA365

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AD7705程序

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AD7705应用注意要点：
   （1） DRDY逻辑不要搞反，高电平时等待转换状态，低电平为可以读取转换数据
   （2）系统校准时输入信号要大于所选量程的4/5，否则校准不到32767。
   （3）校准时要等待一定的时间，读取数据也一样，不能超过转换速率。
   （4）一般的应用只要内部校准，这个很简单，只要初始化就可以。如果测量范围不是芯片的范围，可以通过系统校准来实现，满量程校准电压要大于量程的4/5

#include
#include
#include "ad7705.h"
#include "main.h"
#include "crc16.h"
#include "Usart.h"

//针对四个量程的设置寄存器的设置内容
//（1）对于单极性V级别输入0-5V、0-20mA、0-10V这三个量程，输入范围为0-2V，无极性，增益为1，缓冲模式--0-2V
//（2）对于双极性V级别输入+-2.5V、+-5V这两个量程，输入范围为+-1V，双极性，增益为2，缓冲模式--+-2V
//（3）对于双精度mV级别输入+-500mV，增益为4，双极性，缓冲模式--+-2V
//（4）对双精度mV级别+-50mV，增益为32，双极性，缓冲模式--+-1.6V
//------MD1(0)   MD0(0)   G2(0)   G1(0)   G0(0)   B/U(0)   BUF(0)   FSYNC(0)--------------------------//
const unsigned char text_of_setup[4]={0X04,0X08,0X10,0X28}; //非缓冲模式,数字滤波同步
//const unsigned char text_of_setup[4]={0X06,0X0A,0X12,0X2A}; //缓冲模式，数字滤波同步

extern volatile unsigned char  command[7];   //校准命令全局数组
extern volatile unsigned char  scale;        //记录系统量程
extern volatile unsigned char  NO_CALI_TYPE; //未校准类型
extern volatile unsigned long  int ZS,GS;   //当前量程的校准系数
extern volatile unsigned char  time_count;   //超时标志

//----------------------------------------------------------------------------
//函数：reset_AD7705
//功能：AD7705串行接口失步后将其复位。复位后要延时500us再访问
//参数：无
//返回：无
//变量：无
//备注：无
//----------------------------------------------------------------------------
void reset_AD7705(void)
{
         unsigned char i;

         AD_DIN1;
         for( i=0; i<36; i++ )
         {
                 AD_CLK0;
                 asm("nop");
                 asm("nop");
                      asm("nop");
                 AD_CLK1;
                 asm("nop");
                 asm("nop");
                       asm("nop");
         }

         _delay_ms(1);
}

//------------------------------------------------------------------------------------------
//函数：read_AD7705_byte
//功能：从AD7705读一个字节的数据
//参数：无
//返回：读到的一字节数据
//变量：无
//备注：无
//------------------------------------------------------------------------------------------
unsigned char read_AD7705_byte(void)
{
         unsigned char data = 0;
         unsigned char i = 0;

         for( i=0; i<8; i++ )
         {
                 data <<= 1;
                 AD_CLK0;
                 asm("nop");
                 asm("nop");
                 asm("nop");
                 if(AD_DOUT)
                 {
                   data++;
                 }
                      AD_CLK1;
                 asm("nop");
                 asm("nop");
                 asm("nop");
         }

         return data;
}

//------------------------------------------------------------------------------------------
//函数：read_AD7705_word
//功能：从AD7705读一个字的数据，共16bit
//参数：无
//返回：读到的一字节数据
//变量：无
//备注：无
//------------------------------------------------------------------------------------------
unsigned int read_AD7705_word(void)
{
         unsigned int data = 0;
         unsigned char i = 0;

         for( i=0; i<16; i++ )
         {
                 data <<= 1;
                 AD_CLK0;
                 asm("nop");
                 asm("nop");
                 asm("nop");
                 if(AD_DOUT)
                 {
                    data++;
                 }
                      AD_CLK1;
                 asm("nop");
                 asm("nop");
                 asm("nop");
         }

         return data;
}

//------------------------------------------------------------------------------------------
//函数：read_AD7705_dword
//功能：从AD7705读一个24的数据
//参数：无
//返回：读到的一字节数据
//变量：无
//备注：AD7705是一个24位AD，选定刷新频率在16.7HZ下，有效位是19位，暂时读出全部24位数据
//------------------------------------------------------------------------------------------
unsigned long int read_AD7705_dword(void)
{
         unsigned long data = 0;
         unsigned char i = 0;

         for( i=0; i<24; i++ )
         {
                 data <<= 1;
                 AD_CLK0;
                 asm("nop");
                 asm("nop");
                 asm("nop");
                 if(AD_DOUT)
                 {
                    data++;
                 }
                      AD_CLK1;
                 asm("nop");
                 asm("nop");
                 asm("nop");
         }

         return data;
}

//------------------------------------------------------------------------------------------
//函数：write_AD7705_byte
//功能：往AD7705写8位数据
//参数：IN - uint8_t  data,要写入AD7705的数据
//返回：无
//变量：无
//备注：无
//------------------------------------------------------------------------------------------
void write_AD7705_byte(unsigned char data)
{
         for(unsigned char i=0; i<8; i++)
         {
                 AD_CLK0;
                 if(data&0x80)
                         AD_DIN1;
                 else
                         AD_DIN0;
                      asm("nop");
                 asm("nop");
                 asm("nop");
                 AD_CLK1;
                 asm("nop");
                      asm("nop");
                 asm("nop");
                 data <<= 1;
         }

         AD_DIN1;
}

//------------------------------------------------------------------------------------------
//函数：write_AD7705_dword
//功能：往AD7705写24位数据,因为AD7705是24位的器件
//参数：IN - int32_t  data,要写入AD7705的数据
//返回：无
//变量：无
//备注：无
//------------------------------------------------------------------------------------------
void write_AD7705_dword(unsigned long int data)
{
        for(unsigned char i = 0; i<24; i++)
        {
                 AD_CLK0;
                 if(data&0x800000)
                         AD_DIN1;
                 else
                         AD_DIN0;
                      asm("nop");
                 asm("nop");
                 asm("nop");
                 AD_CLK1;
                 asm("nop");
                       asm("nop");
                 asm("nop");
                 data <<= 1;
         }

         AD_DIN1;
}
[page]
//--------------------------------------------------------------------------
//-------------------------读取AD7705转换数据函数--------------------------
//入口参数：指向main()主函数定义的ad_data变量的常量指针
//--------------------------------------------------------------------------
void ReadData7705(unsigned int *const pdata)
{
     unsigned int data=0, fiter[5]={0};
         unsigned long int temp=0;
         unsigned char i=0, sort_flag=1;

         AD_CS0;
         _delay_us(5);

         start_AD7705();

         for( i=0; i<5; i++ )
         {
               start_timer0();
             _delay_ms(2);
             while( AD_DRDY )
             {
                     if( time_count >= time_read_data )
                     {
                             stop_timer0();
                             AD_CS1;
                             return;
                     }
                 }
             stop_timer0();

               write_AD7705_byte( RD_DATA_REG );
               fiter[i] = read_AD7705_word();
         }
         AD_CS1;

         sort_flag = 1;
         while( sort_flag )
         {
             sort_flag = 0;
             for( i=0; i<4; i++ )
                 {
                     if( fiter[i] > fiter[i+1] )
                         {
                             data = fiter[i];
                                 fiter[i] = fiter[i+1];
                                 fiter[i+1] = data;
                                 sort_flag = 1;
                         }
                 }
         }

         temp = ( (unsigned long int)fiter[1] + (unsigned long int)fiter[2]
                  + (unsigned long int)fiter[3] )/3;

         data = (unsigned int)temp;

                  if( (data<0xfff0) && (data&0x000f)>0x0008 )
         {
             data >>= 4;
                 data++;
         }
         else
         {
             data >>= 4;
         }

     if( 1 != scale )
     {
                 data -= 0x0800;
     }

     *pdata = data & 0x0fff;
}

//---------------------------------------------------------------------------------------
//校准命令格式
//STX        Data Long        Command Code        Parameter        CheckSum        ETX
//0x55        数据长度（2）        量程指示        00H/01H            CRC16(2)        0x0D

void AD7705_calibration(void)
{
              unsigned char readtimes =0;

         unsigned char cali_scale =0;

          unsigned long int temp =0;

          unsigned char coefficient[8] ={0}; //test[8]={0};

         //16位校验和的临时变量
         unsigned int crcvalue =0;

         AD_CS1;

         cali_scale = command[2]; //获取上位机发送的要校准的量程类型

      eeprom_busy_wait();
     eeprom_read_block( &coefficient[0], (void*)(ADDR_EEPROM_1+(cali_scale-1)*10), 8 );
     crcvalue = checksum( &coefficient[0], 6 );
         if( (coefficient[7]*256+coefficient[6]) != crcvalue )
         {
              readtimes++;
         }

         if( 1 == readtimes )
         {
             eeprom_busy_wait();
                eeprom_read_block( &coefficient[0], (void*)(ADDR_EEPROM_2+(cali_scale-1)*10), 8 );
               crcvalue = checksum( &coefficient[0], 6 ); //
             if( (coefficient[7]*256+coefficient[6]) != crcvalue )
             {
                     readtimes++;
             }
         }

         if( 2 == readtimes )
         {
             eeprom_busy_wait();
         eeprom_read_block( &coefficient[0], (void*)(ADDR_EEPROM_3+(cali_scale-1)*10), 8 );
         }

         ADDR409_MASK;
         AD_CS0;
           _delay_us(5);
         reset_AD7705();

         write_AD7705_byte( WR_CLOCK_REG );
         write_AD7705_byte( CLOCK_REG_SET );

         if( ZERO_CALIBRATION == command[3] ) //校准命令为零校准
         {
             write_AD7705_byte( WR_SETUP_REG );
             write_AD7705_byte( text_of_setup[cali_scale-1] | SYS_ZERO_CALI);

                 //等待校准完成
                 start_timer0();
                 while( time_count                  stop_timer0();

                 while( AD_DRDY );

                 //读OFFSET寄存器
                 write_AD7705_byte( RD_OFFSET_REG );
                 temp = read_AD7705_dword();

                 if( cali_scale == scale)
                 {
                     ZS = temp;                                                          NO_CALI_TYPE = NO_FULL_CALIBRATION;
                 }

                 coefficient[0] = (unsigned char)( temp%256 );
                 coefficient[1] = (unsigned char)( (temp/256)%256 );
                 coefficient[2] = (unsigned char)( (temp/65536)%256 );
         }
     else if( FULL_CALIBRATION == command[3] )
     {

           temp = (unsigned long int)(coefficient[0]) + (unsigned long int)(coefficient[1])*256
                      + (unsigned long int)(coefficient[2])*65536;

             write_AD7705_byte( WR_OFFSET_REG );
             write_AD7705_dword( temp );

            write_AD7705_byte( WR_SETUP_REG );
             write_AD7705_byte( text_of_setup[cali_scale-1] | SYS_FULL_CALI );

                 //等待校准完成
                 start_timer0();
                 while( time_count                  stop_timer0();

                 while( AD_DRDY );//
                 //读FULL寄存器
                 write_AD7705_byte( RD_FULL_REG );
                 temp = read_AD7705_dword();

                 if( cali_scale == scale )
                 {
                     GS = temp;
                          NO_CALI_TYPE = ALREADY_CALIBRATION;
                 }

                 coefficient[3] = (unsigned char)( temp%256 );
                 coefficient[4] = (unsigned char)( (temp/256)%256 );
                 coefficient[5] = (unsigned char)( (temp/65536)%256 );
         }
     else
     {
             AD_CS1;
                 _delay_us(5);
                 return;
         }

     AD_CS1;
         _delay_us(5);

         crcvalue = checksum(&coefficient[0],6);
         coefficient[6] = (unsigned char)(crcvalue%256);//
            coefficient[7] = (unsigned char)(crcvalue/256);

              eeprom_busy_wait();
     eeprom_write_block( &coefficient[0], (void*)(ADDR_EEPROM_1+(cali_scale-1)*10), 8 );

              eeprom_busy_wait();
     eeprom_write_block( &coefficient[0], (void*)(ADDR_EEPROM_2+(cali_scale-1)*10), 8 );

                 eeprom_busy_wait();
         eeprom_write_block( &coefficient[0], (void*)(ADDR_EEPROM_3+(cali_scale-1)*10), 8 );

     Txout( &coefficient[0] );//输出校准数据给上位机

         return;
}

//
void start_AD7705(void)
{
     reset_AD7705();

         //写OFFSET寄存器
         write_AD7705_byte( WR_OFFSET_REG );
         write_AD7705_dword( ZS );

         //写满量程校准寄存器
         write_AD7705_byte( WR_FULL_REG );
         write_AD7705_dword( GS );

         //CLOCK寄存器设置，无分频，50HZ输出更新速率
         write_AD7705_byte( WR_CLOCK_REG );
         write_AD7705_byte( CLOCK_REG_SET );

         //写设置寄存器
         write_AD7705_byte( WR_SETUP_REG );
         write_AD7705_byte( text_of_setup[scale-1] );

         start_timer0();
         while( time_count          stop_timer0();
}

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