bloureiro
Joined: 26 Feb 2007
Posts: 6
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| AD7714 |
 Posted: Thu Oct 04, 2007 8:43 am |
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Hi make this driver for a multi-channel acquisitions and works fine.
| Code: |
//*************************************************************
// Routines for AD7714
// write_adc_byte()
// adc_init()
// read_adc_word()
// read_adc_value()
//*************************************************************
//configure PIC ports
#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_B0
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);
}
void adc_init(int8 filterH,int8 filterL)
{
output_low(ADC_RESET);
output_high(ADC_CLK);
output_high(ADC_CS); //Set high to AD7714 chip select low pin
output_high(ADC_RESET); //Set high to AD7714 reset low pin
delay_ms(1000);
write_adc_byte(0x27); //to com register, channel & filter Hi antes 24--------27 datasheet
write_adc_byte(filterH); //to filter hi register 0xCF ------------------------ 4F datasheet
write_adc_byte(0x37); //to com.register, channel & filter low antes 30-------37 datasheet
write_adc_byte(filterL); //to filter low register 00 antes----------------------A0 datasheet
write_adc_byte(0x10); //to com register, channel & mod register
write_adc_byte(0x20); //to mod register, self test
while ( !input(ADC_DRDY) );
while ( input(ADC_DRDY) );
write_adc_byte(0x11); //to com register, channel & mod register
write_adc_byte(0x20); //to mod register, self test
while ( !input(ADC_DRDY) );
while ( input(ADC_DRDY) );
write_adc_byte(0x12); //to com register, channel & mod register
write_adc_byte(0x20); //to mod register, self test
while ( !input(ADC_DRDY) );
while ( input(ADC_DRDY) );
}
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;
switch(canal)
{
case 1:
write_adc_byte(0x58);
break;
case 2:
write_adc_byte(0x59);
break;
case 3:
write_adc_byte(0x5A);break;
case 4:
write_adc_byte(0x5B);break;
case 5:
write_adc_byte(0x5E);break;
}
while ( !input(ADC_DRDY) );
while ( input(ADC_DRDY) );
value=read_adc_word();
return value;
}
float convert_to_volts(int32 temp){
return (float)temp*0.0000000745;//ref 1,25V
}
|
To chose the sampling frequency you will need write the registers of filter
in the adc_init(int8 filterH,int8 filterL). |
|
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