issue with SPI COMMUNICATION WITH AD7173-8, controller ESP32

Hi SRISUS ,

Is the reset value of the ADCMODE register really 0x201 and not 0x2001? 

Can you provide a digital interface scope shot for this? 

You may also want to refer to Digital Interface FAQ - Sigma Delta ADC - Q&A - Precision ADCs - EngineerZone (analog.com). The number 8 FAQ might be able to answer this query or maybe help you understand the data you are reading. Thank you.

Regards,

Rod

Hi SRISUS ,

Is the reset value of the ADCMODE register really 0x201 and not 0x2001? 

Can you provide a digital interface scope shot for this? 

You may also want to refer to Digital Interface FAQ - Sigma Delta ADC - Q&A - Precision ADCs - EngineerZone (analog.com). The number 8 FAQ might be able to answer this query or maybe help you understand the data you are reading. Thank you.

Regards,

Rod

Hi RAdante,

thanks for your response, 

as per the datasheet ADCMODE reset value is 0x2000. but when I read that register it is giving 0x201

here correct reset value is 0x2000

so, what could be the issue?

thanks & regards

Srinivasa

Hi,

Can you provide a digital interface scope shot for this? So that we can better understand the output you are reading. Thanks.

Regards,

Rod

Hi RAdante,

sorry for the late response

I have changed the frequency of the SPI protocol and now it reads the register reset value properly.

I have configured all the required registers but conversion not happening.

I am getting output as 000. here I have attached the code below,

please let me know if anything is configured wrong or if any other issue

-----------------------------------------------------------------------------------
main code
-----------------------------------------------------------------------------------

#include "AD7173_8.h"

void setup() {
	/* initiate serial communication */
	Serial.begin(230400);

	/* initialize SPI connection to the ADC */
	AD7173.init();

	/* sync the ADC */
	AD7173.sync();

	/* reset the ADC registers to default */
	AD7173.reset();

	/* check if the ID register of the ADC is valid */
	if (AD7173.is_valid_id()) Serial.println("AD7173 ID is valid");
	else Serial.println("AD7173 ID is invalid");

	/* set ADC input channel configuration */
	/* enable channel 0 and channel 1 and connect each to 2 analog inputs for bipolar input */
	/* CH0 - CH15 */
	/* true/false to enable/disable channel */
	/* SETUP0 - SETUP7 */
	/* AIN0 - AIN16 */
Serial.println("nexrt process");
	AD7173.set_channel_config(CH3, true, SETUP0, AIN3, AIN2);
	//AD7173.set_channel_config(CH1, true, SETUP0, AIN2, AIN3);

	/* set the ADC SETUP0 coding mode to BIPLOAR output */
	/* SETUP0 - SETUP7 */
	/* BIPOLAR, UNIPOLAR */
	/* AIN_BUF_DISABLE, AIN_BUF_ENABLE */
	/* REF_EXT, REF_AIN, REF_INT, REF_PWR */
	AD7173.set_setup_config(SETUP0, BIPOLAR, AIN_BUF_DISABLE, REF_EXT);

	/* set ADC OFFSET0 offset value */
	/* OFFSET0 - OFFSET7 */
	AD7173.set_offset_config(OFFSET0, 0);

	/* set the ADC FILTER0 ac_rejection to false and samplingrate to 1007 Hz */
	/* FILTER0 - FILTER7 */
	/* SPS_1, SPS_2, SPS_5, SPS_10, SPS_16, SPS_20, SPS_49, SPS_59, SPS_100, SPS_200 */
	/* SPS_381, SPS_503, SPS_1007, SPS_2597, SPS_5208, SPS_10417, SPS_15625, SPS_31250 */
	AD7173.set_filter_config(FILTER0,  SPS_5);

	/* set the ADC data and clock mode */
	/* CONTINUOUS_CONVERSION_MODE, SINGLE_CONVERSION_MODE */
	/* in SINGLE_CONVERSION_MODE after all setup channels are sampled the ADC goes into STANDBY_MODE */
	/* to exit STANDBY_MODE use this same function to go into CONTINUOUS or SINGLE_CONVERSION_MODE */
	/* INTERNAL_CLOCK, INTERNAL_CLOCK_OUTPUT, EXTERNAL_CLOCK_INPUT, EXTERNAL_CRYSTAL */
	/* REF_DISABLE, REF_ENABLE */
	AD7173.set_adc_mode_config(CONTINUOUS_CONVERSION_MODE, INTERNAL_CLOCK, REF_DISABLE);

	/* enable/disable CONTINUOUS_READ_MODE and appending STATUS register to data */
	/* to exit CONTINUOUS_READ_MODE use AD7173.reset(); */
	/* AD7173.reset(); returns all registers to default state, so everything has to be setup again */
	/* true / false to enable / disable appending status register to data, 4th byte */
	AD7173.set_interface_mode_config(false, true);
Serial.println("nexrt process started");
	/* wait for ADC */
	delay(10);
}

/* ADC conversion data and STATUS register */
byte data[4];

void loop() {
	/* when ADC conversion is finished */
	if (DATA_READY) {
		/* get ADC conversion result */
    Serial.println("DATA READY");
		AD7173.get_data(data);

		/* send result via serial */
		Serial.print(data[0], HEX);
		Serial.print(data[1], HEX);
		Serial.println(data[2], HEX);
		Serial.println(data[3], HEX);
		delay(10);
	}
else
{
     Serial.println("DATA not READY");
  
}  
		delay(1000);


}

-----------------------------------------------------------------------------------------------------------
AD7173_8.CPP
-----------------------------------------------------------------------------------------------------------
#include "AD7173_8.h"

AD7173Class AD7173;

void AD7173Class::init() {
	/* initiate SPI communication */
	SPI.begin();
	/* use SPI mode 3 */
  SPI.setFrequency(5000000);
	SPI.setDataMode(SPI_MODE3);
	/* allow the LDOs to power up */
	delay(10);
}

void AD7173Class::reset() {
	/* sending at least 64 high bits returns ADC to default state */
	for (int i = 0; i < 8; i++) {
		SPI.transfer(0xFF);
	}
	/* allow the LDOs to power up */
	delay(10);
}

void AD7173Class::sync() {
	/* toggle the chip select */
	digitalWrite(SS, HIGH);
	delay(10);
	digitalWrite(SS, LOW);
	/* allow the LDOs to power up */
	delay(10);
}

void AD7173Class::print_byte(byte value) {
	char format[10];
	sprintf(format, "0x%.2X ", value);
	Serial.print(format);
}

int AD7173Class::set_register(adc7173_register_t reg, byte *value, int value_len) {
	/* send communication register id 0x00 */
  digitalWrite(SS, LOW);
	SPI.transfer(0x00);
	/* send write command to the desired register 0x00 - 0xFF */
	SPI.transfer(0x00 | reg);
	/* send the desired amount of bytes */
	for (int i = 0; i < value_len; i++) {
		SPI.transfer(value[i]);
	}
  digitalWrite(SS, HIGH);
	/* when debug enabled */
	if (DEBUG_ENABLED) {
		Serial.print("set_register: set [ ");
		for (int i = 0; i < value_len; i++) {
			this->print_byte(value[i]);
		}
		Serial.print("] to reg [ ");
		this->print_byte(reg);
		Serial.println("]");
	}
	/* TODO: find out correct delay */
	delay(READ_WRITE_DELAY);
	/* return error code */
	return 0;
}

int AD7173Class::get_register(adc7173_register_t reg, byte *value, int value_len) {
	/* send communication register id 0x00 */
   digitalWrite(SS, LOW);
	SPI.transfer(0x00);
	/* send read command to the desired register 0x00 - 0xFF */
	SPI.transfer(0x40 | reg);
	/* receive the desired amount of bytes */
	for (int i = 0; i < value_len; i++) {
		value[i] = SPI.transfer(0x00);
	}
  digitalWrite(SS, HIGH);
	/* when debug enabled */
	if (DEBUG_ENABLED) {
		Serial.print("get_register: got [ ");
		for (int i = 0; i < value_len; i++) {
			this->print_byte(value[i]);
		}
		Serial.print("] from reg [ ");
		this->print_byte(reg);
		Serial.println(" ]");
	}
	/* TODO: find out correct delay */
	delay(READ_WRITE_DELAY);
	/* return error code */
	return 0;
}

int AD7173Class::get_current_data_channel(adc7173_register_t &channel) {
	/* Address: 0x00, Reset: 0x80, Name: STATUS */

	/* get ADC status register */
	byte value[1];
	this->get_register(STATUS_REG, value, 1);

	/* assign to return channel register value */
	channel = (adc7173_register_t) (value[0] & 0x0F);

	/* return error code */
	return 0;
}

int AD7173Class::set_adc_mode_config(data_mode_t data_mode, clock_mode_t clock_mode, ref_mode_t ref_mode) {
	/* Address: 0x01, Reset: 0x2000, Name: ADCMODE */

	/* prepare the configuration value */
	/* REF_EN [15], RESERVED [14], SING_CYC [13], RESERVED [12:11], DELAY [10:8], RESERVED [7], MODE [6:4], CLOCKSEL [3:2], RESERED [1:0] */
	byte value[2] = {0x00, 0x00};
	value[1] = (data_mode << 4) | (clock_mode << 2);
	value[0] = (ref_mode << 7)|(1<<5);

	/* update the configuration value */
	this->set_register(ADCMODE_REG, value, 2);

	/* verify the updated configuration value */
	this->get_register(ADCMODE_REG, value, 2);

	/* return error code */
	return 0;
}

int AD7173Class::set_interface_mode_config(bool continuous_read, bool append_status_reg) {
	/* Address: 0x02, Reset: 0x0000, Name: IFMODE */

	/* prepare the configuration value */
	/* RESERVED [15:13], ALT_SYNC [12], IOSTRENGTH [11], HIDE_DELAY [10], RESERVED [9], DOUT_RESET [8], CONTREAD [7], DATA_STAT [6], REG_CHECK [5], RESERVED [4], CRC_EN [3:2], RESERVED [1], WL16 [0] */
	byte value[2] = {0x00, 0x00};
	value[1] = (continuous_read << 7) | (append_status_reg << 6);

	/* update the configuration value */
	this->set_register(IFMODE_REG, value, 2);

	/* verify the updated configuration value */
	this->get_register(IFMODE_REG, value, 2);

	/* when continuous read mode */
	if (continuous_read) {
		/* update the data mode */
		this->m_data_mode = CONTINUOUS_READ_MODE;
	}

	/* enable or disable appending status reg to data */
	this->append_status_reg = append_status_reg;

	/* return error code */
	return 0;
}

int AD7173Class::get_data(byte *value) {
	/* Address: 0x04, Reset: 0x000000, Name: DATA */
 digitalWrite(SS, LOW);
	/* when not in continuous read mode, send the read command */
	if (this->m_data_mode != CONTINUOUS_READ_MODE) {
		/* send communication register id 0x00 */
		SPI.transfer(0x00);
		/* send read command 0x40 to the data register 0x04 */
		SPI.transfer(0x40 | DATA_REG);
	}
	/* get the ADC conversion result (24 bits) */
	value[0] = SPI.transfer(0x00);
	value[1] = SPI.transfer(0x00);
	value[2] = SPI.transfer(0x00);
	/* when status register appending is enabled */
	if (this->append_status_reg) {
		value[3] = SPI.transfer(0x00);
	}
	// digitalWrite(SS, HIGH);
	/* when debug enabled */
	if (DEBUG_ENABLED) {
		Serial.print("get_data: read [ ");
		this->print_byte(value[0]);
		this->print_byte(value[1]);
		this->print_byte(value[2]);
		/* when status register appending is enabled */
		if (this->append_status_reg) {
			this->print_byte(value[3]);;
		}
		Serial.println("] from reg [ 0x04 ]");
	}
	/* return error code */
	return 0;
}

bool AD7173Class::is_valid_id() {
	/* Address: 0x07, Reset: 0x30DX, Name: ID */

	/* get the ADC device ID */
	byte id[2];
	this->get_register(ID_REG, id, 2);
	/* check if the id matches 0x30DX, where X is don't care */
	//id[1] &= 0xF0;
	bool valid_id = id[0] == 0x30 && id[1] == 0xD5;
Serial.print("init: ADC device ID is invalid :( [ ");
      	Serial.print(id[0],HEX);
        	Serial.print(id[1],HEX);
	/* when debug enabled */
	if (DEBUG_ENABLED) {
		if (valid_id) {
			Serial.println("init: ADC device ID is valid :)");
		} else {
			Serial.print("init: ADC device ID is invalid :( [ ");
      	Serial.print(id[0]);
        	Serial.print(id[1]);
			this->print_byte(id[0]);
			this->print_byte(id[1]);
			Serial.print(" ]");
			Serial.println();
		}
	}
	/* return validity of ADC device ID */
	return valid_id;
}

int AD7173Class::set_channel_config(adc7173_register_t channel, bool enable, adc7173_register_t setup, analog_input_t ain_pos, analog_input_t ain_neg) {
	/* Address: 0x10, Reset: 0x8001, Name: CH0 */
	/* Address Range: 0x11 to 0x1F, Reset: 0x0001, Name: CH1 to CH15 */

	/* prepare the configuration value */
	/* CH_EN0 [15], SETUP_SEL0 [14:12], RESERVED [11:10], AINPOS0 [9:5], AINNEG0 [4:0] */
	byte value[2] = {0x00, 0x00};
	value[0] = (enable << 7) | (setup << 4) | (ain_pos >> 3);
	value[1] = (ain_pos << 5) | ain_neg;

	/* update the configuration value */
	this->set_register(channel, value, 2);

	/* verify the updated configuration value */
	this->get_register(channel, value, 2);

	/* return error code */
	return 0;
}

int AD7173Class::set_setup_config(adc7173_register_t setup, coding_mode_t coding_mode, ain_buf_mode_t ain_buf_mode, setup_ref_source_t setup_ref_source) {
	/* Address Range: 0x20 to 0x27, Reset: 0x1000, Name: SETUPCON0 to SETUPCON7 */

	/* prepare the configuration value */
	byte value[2] = {0x00, 0x00};
	value[0] = (coding_mode << 4) | ain_buf_mode;
	value[1] = (setup_ref_source << 4);

	/* update the configuration value */
	this->set_register(setup, value, 2);

	/* verify the updated configuration value */
	this->get_register(setup, value, 2);

	/* return error code */
	return 0;
}

int AD7173Class::set_filter_config(adc7173_register_t filter, data_rate_t data_rate) {
	/* Address Range: 0x28 to 0x2F, Reset: 0x0000, Name: FILTCON0 to FILTCON7 */

	/* prepare the configuration value */
	byte value[2] = {0x00, 0x00};
	/* SINC3_MAP0 [15], RESERVED [14:12], ENHFILTEN0 [11], ENHFILT0 [10:8], RESERVED [7], ORDER0 [6:5], ORD0 [4:0] */
	value[1] = data_rate;

	/* update the configuration value */
	this->set_register(filter, value, 2);

	/* verify the updated configuration value */
	this->get_register(filter, value, 2);

	/* return error code */
	return 0;
}

int AD7173Class::set_offset_config(adc7173_register_t offset, uint32_t offset_value) {
	/* Address Range: 0x30 to 0x37, Reset: 0x0000, Name: OFFSET0 to OFFSET7 */

	/* add the default offset value */
	offset_value += 8388608;
	/* prepare the configuration value */
	byte value[3] = {0x00, 0x00, 0x00};
	value[0] = offset_value >> 16;
	value[1] = offset_value >> 8;
	value[2] = offset_value;

	/* update the configuration value */
	this->set_register(offset, value, 3);

	/* verify the updated configuration value */
	this->get_register(offset, value, 3);

	/* return error code */
	return 0;
}




----------------------------------------------------------------------------------------------------------------------------------
AD7173_8.h file
----------------------------------------------------------------------------------------------------------------------------------
#ifndef _AD7173_H_INCLUDED
#define _AD7173_H_INCLUDED

#if ARDUINO >= 100
#include "Arduino.h"
#else
#include "WProgram.h"
#endif

#include "SPI.h"

/* enable or disable debug */
#define DEBUG_ENABLED 0

/* delay for reading and writing registers  */
#define READ_WRITE_DELAY 1

/* registers */
typedef enum {
	/* other ADC registers */
	COMMS_REG = 0x00,
	STATUS_REG = 0x00,
	ADCMODE_REG = 0x01,
	IFMODE_REG = 0x02,
	REGCHECK_REG = 0x03,
	DATA_REG = 0x04,
	GPIOCON_REG = 0x06,
	ID_REG = 0x07,
	/* ADC channel registers */
	CH0 = 0x10,
	CH1 = 0x11,
	CH2 = 0x12,
	CH3 = 0x13,
	CH4 = 0x14,
	CH5 = 0x15,
	CH6 = 0x16,
	CH7 = 0x17,
	CH8 = 0x18,
	CH9 = 0x19,
	CH10 = 0x1A,
	CH11 = 0x1B,
	CH12 = 0x1C,
	CH13 = 0x1D,
	CH14 = 0x1E,
	CH15 = 0x1F,
	/* ADC setup config register */
	SETUP0 = 0x20,
	SETUP1 = 0x21,
	SETUP2 = 0x22,
	SETUP3 = 0x23,
	SETUP4 = 0x24,
	SETUP5 = 0x25,
	SETUP6 = 0x26,
	SETUP7 = 0x27,
	/* ADC filter config registers */
	FILTER0 = 0x28,
	FILTER1 = 0x29,
	FILTER2 = 0x2A,
	FILTER3 = 0x2B,
	FILTER4 = 0x2C,
	FILTER5 = 0x2D,
	FILTER6 = 0x2E,
	FILTER7 = 0x2F,
	/* ADC offset registers */
	OFFSET0 = 0x30,
	OFFSET1 = 0x31,
	OFFSET2 = 0x32,
	OFFSET3 = 0x33,
	OFFSET4 = 0x34,
	OFFSET5 = 0x35,
	OFFSET6 = 0x36,
	OFFSET7 = 0x37,
	/* ADC gain registers */
	GAIN0 = 0x38,
	GAIN1 = 0x39,
	GAIN2 = 0x3A,
	GAIN3 = 0x3B,
	GAIN4 = 0x3C,
	GAIN5 = 0x3D,
	GAIN6 = 0x3E,
	GAIN7 = 0x3F
} adc7173_register_t;

/* ADC analog inputs */
typedef enum {
	AIN0 = 0x00,
	AIN1 = 0x01,
	AIN2 = 0x02,
	AIN3 = 0x03,
	AIN4 = 0x04,
	AIN5 = 0x05,
	AIN6 = 0x06,
	AIN7 = 0x07,
	AIN8 = 0x08,
	AIN9 = 0x09,
	AIN10 = 0x0A,
	AIN11 = 0x0B,
	AIN12 = 0x0C,
	AIN13 = 0x0D,
	AIN14 = 0x0E,
	AIN15 = 0x0F,
	AIN16 = 0x10,
	/* other ADC analog inputs */
	TEMP_SENSOR_POS = 0x11,
	TEMP_SENSOR_NEG = 0x12,
	REF_POS = 0x15,
	REF_NEG = 0x16
} analog_input_t;

/* ADC filter data rates (samples per second) */
/* some are are rounded down, the data rates are for sinc5 + sinc1 */
typedef enum {
	SPS_31250 = 0x00,
	SPS_15625 = 0x06,
	SPS_10417 = 0x07,
	SPS_5208 = 0x08,
	SPS_2597 = 0x09,
	SPS_1007 = 0x0A,
	SPS_503 = 0x0B,
	SPS_381 = 0x0C,
	SPS_200 = 0x0D,
	SPS_100 = 0x0E,
	SPS_59 = 0x0F,
	SPS_49 = 0x10,
	SPS_20 = 0x11,
	SPS_16 = 0x12,
	SPS_10 = 0x13,
	SPS_5 = 0x14,
	SPS_2 = 0x15,
	SPS_1 = 0x16
} data_rate_t;

/* ADC setup coding modes */
typedef enum {
	UNIPOLAR = 0x00,
	BIPOLAR = 0x01
} coding_mode_t;

/* ADC data conversion modes */
typedef enum {
	CONTINUOUS_CONVERSION_MODE = 0x00,
	SINGLE_CONVERSION_MODE = 0x01,
	CONTINUOUS_READ_MODE
} data_mode_t;

/* clock mode */
/*
	00 Internal oscillator
	01 Internal oscillator output on XTAL2/CLKIO pin
	10 External clock input on XTAL2/CLKIO pin
	11 External crystal on XTAL1 and XTAL2/CLKIO pins
*/
typedef enum {
	INTERNAL_CLOCK = 0x00,
	INTERNAL_CLOCK_OUTPUT = 0x01,
	EXTERNAL_CLOCK_INPUT = 0x02,
	EXTERNAL_CRYSTAL = 0x03
} clock_mode_t;

/* ADC internal reference modes */
typedef enum {
	REF_DISABLE = 0x00,
	REF_ENABLE = 0x01
} ref_mode_t;

/* ADC channel buffer setting */
typedef enum {
	AIN_BUF_DISABLE = 0x00,
	AIN_BUF_ENABLE = 0x03
} ain_buf_mode_t;

/* setup to select reference source */
/*
	00 External reference source
	01 AIN1/REF2+ and AIN0/REF2−
	10 Internal reference source
	11 External AVDD1 – AVSS
*/
typedef enum {
	REF_EXT = 0x00,
	REF_AIN = 0x01,
	REF_INT = 0x02,
	REF_PWR = 0x03
} setup_ref_source_t;

/* ADC data ready indicator */
#define DATA_READY digitalRead(MISO) == LOW

class AD7173Class {
public:
	/*
	=====================================
	constructor
	set default ADC setup coding mode
	set default ADC data conversion mode
	=====================================
	*/
	AD7173Class() : m_data_mode(CONTINUOUS_CONVERSION_MODE), append_status_reg(false) {
		/* ... */
	}

	/*
	============================================
	initializes the SPI connection with the ADC
	============================================
	*/
	void init();

	/*
	==================================================
	cancels the current transaction to resync the ADC
	==================================================
	*/
	void sync();

	/*
	==============================================
	resets the ADC registers to the default state
	==============================================
	*/
	void reset();

	/*
	=============================================
	gets the current conversion results channel
	@param byte - current data channel
	@return int - error code
	=============================================
	*/
	int get_current_data_channel(adc7173_register_t &);

	/*
	================================
	sets the ADC mode configuration
	@param clock_mode_t - clock mode
	@return int - error code
	================================
	*/
	int set_adc_mode_config(data_mode_t, clock_mode_t, ref_mode_t);

	/*
	==================================================
	sets the ADC interface mode configuration
	@param bool - ensable/disable continuous read mode
	@return int - error code
	==================================================
	*/
	int set_interface_mode_config(bool, bool);

	/*
	==========================================
	gets the ADC conversion result
	@return byte[] - the ADC conversion result
	==========================================
	*/
	int get_data(byte *);

	/*
	============================================
	checks the ID register of the ADC
	@return bool - true if the ADC ID valid
	============================================
	*/
	bool is_valid_id();

	/*
	=====================================
	configures ADC channels
	@param byte - channel register
	@param bool - enable/disable channel
	@param byte - setup register
	@param byte - analog input positive
	@param byte - analog input negative
	@return int - error code
	=====================================
	*/
	int set_channel_config(adc7173_register_t, bool, adc7173_register_t, analog_input_t, analog_input_t);

	/*
	==================================
	sets the ADC setups coding mode
	@param byte - setup register
	@param condig_mode_t - coding mode
	@param ain_buf_t - analog input buffer
	@return int - error code
	==================================
	*/
	int set_setup_config(adc7173_register_t, coding_mode_t, ain_buf_mode_t, setup_ref_source_t);

	/*
	==========================================
	sets the ADC filters data conversion rate
	@param byte - filter register
	@param byte - data rate
	@return int - error code
	==========================================
	*/
	int set_filter_config(adc7173_register_t, data_rate_t);

	/*
	======================================
	sets the ADC offset compensation value
	@param byte - offset register
	@param uint32_t - offset value
	@return int - error code
	======================================
	*/
	int set_offset_config(adc7173_register_t, uint32_t);

private:
	/* ADC data mode */
	data_mode_t m_data_mode;
	
	/* Append status register to data */
	bool append_status_reg;

	/*
	===========================
	print bytes in nice format
	@param byte - byte to print
	===========================
	*/
	void print_byte(byte);

	/*
	=======================================
	set a desired ADC register value
	@param byte - the register to set
	@param  byte[] - the bytes to set
	@param int - the length of bytes to set
	=======================================
	*/
	int set_register(adc7173_register_t, byte *, int);

	/*
	=======================================
	get a desired ADC register value
	@param byte - the register to get
	@param int - the length of bytes to get
	@return byte[] - the ADC register value
	=======================================
	*/
	int get_register(adc7173_register_t, byte *, int);
};

extern AD7173Class AD7173;

#endif

thanks&regards,

srinivasa

Hi SRISUS ,

To determine the end of conversion status in single conversion mode, could you try to poll the RDY[7] bit in the status register (Address:0x0)? 

In Continuous conversion mode, could you try to source the MISO pin as a source of interrupt to determine the Low signal before the data is being read?

Regards,

Janani Sunil

Hi SRISUS ,

Just to add a suggestion, can you also monitor the Status Register (0x00) to check if an error in case an undervoltage has occurred.

Regards,

JC

Hi JC

as you suggested I have read the status register and its value are 0x80. 

DOUT/RDY  pin not going LOW.

 thanks & regards

Srinivasa

Hi Janani,

as you said I did both. I have been monitoring the MISO pin it is not going LOW.

thanks & regards

Srinivasa

Hi, SRISUS 

When monitoring the MISO pin, can you confirm that you pull /CS low? 

I would recommend to follow these steps for debugging purposes. 

For example, upon power up when registers are all at default configuration. Stop reading the conversions, just monitor the DRDY pin (when /CS low). Do you see that the pin is pulsing at default ODR (i.e. 6.211ksps)? If yes, try to change the programmed ODR by writing to its appropriate register (FILTCON register). After that, try to readback the same register to see if it was successfully updated. If the readback is okay, try again to monitor the DRDY pin (when /CS is low) and check if the pin is now pulsing at the new programmed ODR. If everything is okay, you can start changing other register based on your target configuration. I would suggest to change it one at a time just to debug where the issue is coming from. 

When DOUT/RDY stops pulsing at any time and it stays high or low (even though the ADC is configured for continuous conversion mode), this indicates that the serial interface has become asynchronous (incorrect number of SCLK pulses, glitches on the SCLK line). Ensure that the correct number of SCLK pulses are being used for each read/write operation. It is also recommended to tie DIN and SCLK high when they are not being used to prevent glitches affecting the SPI interface.

Thanks,
Jellenie

Hi Jellenie,

thanks for your response.

happy to share that I can able to read when DOUT/RDY goes low and conversion is happening properly as expected for a single supply(i.e for 0v to 2.5 reference voltage). 

now I am working on split supply(i.e for -2.5v to 2.5v reference) in this I am not able to read for the full range. in split supply, I can able to read from -1.99v to +1.99v.

can you please suggest to me to solve this issue?

thanks&regards

Srinivasa

Hi SRISUS 

Can you share your input setup please? For example what is your input voltage at AVDD, AVSS, IOVDD, REFIN+, REFIN-, AIN+ and AIN-?

Thanks,

Jellenie