CCS C Software and Maintenance Offers
FAQFAQ   FAQForum Help   FAQOfficial CCS Support   SearchSearch  RegisterRegister 

ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

CCS does not monitor this forum on a regular basis.

Please do not post bug reports on this forum. Send them to CCS Technical Support
AD7714 Driver Help!!

 
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion
View previous topic :: View next topic  
Author Message
bloureiro



Joined: 26 Feb 2007
Posts: 6

View user's profile Send private message

AD7714 Driver Help!!
PostPosted: Wed Mar 07, 2007 6:26 am     Reply with quote
Hi

I'm trying make the driver for AD7714, I've two problems.
The driver is working the basic.

The i can read the channels but i try read the channel 2 the adc send-me the value of channel 1.
The another problem is when I try read some channel I need use self-calibration first and then read the value.

the self-calibration put the program slow.

Code:

//*************************************************************
// Driver routines for the AD7714 chip, by ToHu
// write_adc_byte()
// adc_init()
// read_adc_word()
// read_adc_value()
//*************************************************************

//connection pins to the PIC
#define ADC_DRDY  PIN_B1
#define ADC_DO    PIN_B2
#define ADC_DI    PIN_B3
#define ADC_RESET PIN_B4
#define ADC_CS    PIN_B5
#define ADC_CLK   PIN_B6

void write_adc_byte(int data)
{
   int i;
   output_low(ADC_CS);
   for(i=1;i<=8;++i)
   {
      output_low(ADC_CLK);
      output_bit(ADC_DI, shift_left(&data,1,0));
      output_high(ADC_CLK);
   }
   output_high(ADC_CS);
}

adc_init()
{
   output_low(ADC_RESET);
   output_high(ADC_CLK);
   output_high(ADC_CS); //Set low to AD7714 chip select low pin
   output_high(ADC_RESET); //Set high to AD7714 reset low pin
   delay_ms(2000);
   write_adc_byte(0x27); //to com.register, chanel & filter Hi  antes 24----27 datacheat
   write_adc_byte(0xC0); //to filter hi register  0xCF gasta menos do sinal analogico  4F data cheat
   write_adc_byte(0x37); //to com.register, chanel & filter low  antes 30       37  data cheat
   write_adc_byte(0x13); //to filter low register  00 antes-------------------------------A0 data cheat
   write_adc_byte(0x17); //to com register, chanel & mod register               17 data cheat
   write_adc_byte(0x20); //to mod register, self test---------------------------20
}



int32 read_adc_word()
{
   int i;
   int32 data;
   output_low(ADC_CS);
   for(i=1;i<=24;++i)
   {
      output_low(ADC_CLK);
      output_high(ADC_CLK);
      shift_left(&data,3,input(ADC_DO));
   }
   output_high(ADC_CS);
   return data;
}



int32 read_adc_value(int canal)
{
   int32 value;
   //while ( input(ADC_DRDY) );
   //while ( !input(ADC_DRDY) );
   while ( input(ADC_DRDY) ); // Loop until data is ready

   switch(canal)
   {
      case 1:
      write_adc_byte(0x10); //to com register, chanel & mod register
      write_adc_byte(0x20); //to mod register, self test
      write_adc_byte(0x58);//communications register set to read AIN1
      break;

      case 2:
      write_adc_byte(0x11); //to com register, chanel & mod register
      write_adc_byte(0x20); //to mod register, self test
      write_adc_byte(0x59);//communications register set to read AIN2
      break;

      case 3:
      write_adc_byte(0x12); //to com register, chanel & mod register
      write_adc_byte(0x20); //to mod register, self test
      write_adc_byte(0x5A);break;

      case 4:
      write_adc_byte(0x13); //to com register, chanel & mod register
      write_adc_byte(0x20); //to mod register, self test
      write_adc_byte(0x5B);break;

      case 5:
      write_adc_byte(0x16); //to com register, chanel & mod register
      write_adc_byte(0x20); //to mod register, self test
      write_adc_byte(0x5E);break;
   }
   value=read_adc_word();

   return value;
}

float convert_to_volts(int32 temp){
   return (float)temp*0.000000149;
}


Thanks
Humberto



Joined: 08 Sep 2003
Posts: 1215
Location: Buenos Aires, La Reina del Plata

View user's profile Send private message

PostPosted: Wed Mar 07, 2007 8:57 am     Reply with quote
Quote:

The i can read the channels but i try read the channel 2 the adc send-me the value of channel 1.


The AD is performing according to the code.
In the switch statement, you are consulting the Ch2 but addressing Ch1
(0x11 should be 0x12)
Code:

      case 2:
      write_adc_byte(0x11); //to com register, chanel & mod register


You should load the communication register outside of the switch statement
with the value 0x0F/0x6F and then polling waiting that RDY become true, then you
can read each input channel inside the switch()

Humberto
Display posts from previous:   
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion All times are GMT - 6 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group