Source code for ad7705,can't read data form ch1.

[kuosda]

#include <18F452.h>
#FUSES HS,NOOSCSEN,NOBROWNOUT,NOWDT,NOPUT
#USE DELAY(CLOCK=8000000)
#USE RS232(BAUD=9600,XMIT=PIN_C6,RCV=PIN_C7,BITS=8,PARITY=N)

#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

#define ADC_NORMAL 0x00
#define ADC_SELF 0x40
#define ADC_ZERO_SCALE 0x80
#define ADC_FULL_SCALE 0xc0

#define ADC_GAIN_1 0x00
#define ADC_GAIN_2 0x08
#define ADC_GAIN_4 0x10
#define ADC_GAIN_8 0x18
#define ADC_GAIN_16 0x20
#define ADC_GAIN_32 0x28
#define ADC_GAIN_64 0x30
#define ADC_GAIN_128 0x38

#define ADC_BIPOLAR 0x04
#define ADC_UNIPOLAR 0x00

#define ADC_50 0x04
#define ADC_60 0x05
#define ADC_250 0x06
#define ADC_500 0x07

void write_adc_byte(byte data)
{
byte 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);
}

long int read_adc_word()
{
byte i;
long data;
output_low(ADC_CS);
for(i=1;i<=16;++i) {
output_low(ADC_CLK);
output_high(ADC_CLK);
shift_left(&data,2,input(ADC_DO));
}
output_high(ADC_CS);
return data;
}

void setup_adc_device(int calmode, int gainsetting, int operation, int rate)
{
write_adc_byte( 0x20 );//Communications Register set to write of clock register
write_adc_byte( 0x0C );//Clock Register info here
write_adc_byte( rate );//Clock Register info here
write_adc_byte( calmode|gainsetting|operation);//Setup Register info here
}

void adc_init()
{
output_low(ADC_RESET);
output_high(ADC_CLK);
output_high(ADC_CS);
output_high(ADC_RESET);
setup_adc_device(ADC_SELF,ADC_GAIN_1,ADC_BIPOLAR,ADC_50);
delay_ms(3000);
}

long int read_adc_value(int1 ch)
{
long int value=0;
while ( !input(ADC_DRDY) );
if(ch)
write_adc_byte(0x38);//read of channel 1
else
write_adc_byte(0x39);//read of channel 0

value=read_adc_word();
while ( input(ADC_DRDY) );
return value;
}

void adc_disable()
{
write_adc_byte( 0x20 );
write_adc_byte( 0x10 );
}

float convert_to_volts(long data){
return ((float)data*2.5/0xffff);
}

main() {

static long AD_CH0=0,AD_CH1=0;

DELAY_MS(80);
printf("POWER ON\n\r");

while(true)
{
adc_init();
AD_CH0 = read_adc_value(0);
AD_CH1 = read_adc_value(1);
printf("CH0:\%04LX CH1:\%04LX \r\n",AD_CH0,AD_CH1);
adc_disable();
}
}
___________________________
This message was ported from CCS's old forum
Original Post ID: 13388

[Sherpa Doug]

:= while(true)
:= {
:= adc_init();
:= AD_CH0 = read_adc_value(0);
:= AD_CH1 = read_adc_value(1);
:= printf("CH0:\%04LX CH1:\%04LX \r\n",AD_CH0,AD_CH1);
:= adc_disable();
:= }
:=}

What output do you get from CH0 & CH1?
Do you need a delay between the two read_adc_value statements for the A/D front end to settle?


___________________________
This message was ported from CCS's old forum
Original Post ID: 13404

[championx]

im having de exact same problem? does enyone fixed this? i need to use the 2 channels.