ESP32 Arduino AD7705 SPI Library

[RobFox]

Does anyone know of a library that I can use with an AD7705, communicating using SPI, to and ESP32 using the Arduino IDE?

[jgustavoam]

Hi ,
My suggestion is that you study AD7705 datasheet and convert Arduino Libray to ESP32 Library .
http://www.analog.com/media/en/technica ... 5_7706.pdf
https://github.com/kerrydwong/AD770X

[zacilaci]

Hi !

I have tried to do what you suggested jgustavoam, but with no luck sadly. Could you help me perhaps? Or is there any open-source code available now? I tried github but with no luck sadly.

You can see my modifications below:

.cpp file

Code: AD7705.cpp Select all

/*

 * AD7705/AD7706 Library

 * Kerry D. Wong

 * http://www.kerrywong.com

 * Initial version 1.0 3/2011

 * Updated 1.1 4/2012

 */



#include "AD7705.h"



//write communication register

//   7        6      5      4      3      2      1      0

//0/DRDY(0) RS2(0) RS1(0) RS0(0) R/W(0) STBY(0) CH1(0) CH0(0)



SPIClass vspi(VSPI);



void AD770X::setNextOperation(byte reg, byte channel, byte readWrite) {

    byte r = 0;

    r = reg << 4 | readWrite << 3 | channel;



    //digitalWrite(pinCS, LOW);

    spiTransfer(r);

    //digitalWrite(pinCS, HIGH);

}



//Clock Register

//   7      6       5        4        3        2      1      0

//ZERO(0) ZERO(0) ZERO(0) CLKDIS(0) CLKDIV(0) CLK(1) FS1(0) FS0(1)

//

//CLKDIS: master clock disable bit

//CLKDIV: clock divider bit



void AD770X::writeClockRegister(byte CLKDIS, byte CLKDIV, byte outputUpdateRate) {

    byte r = CLKDIS << 4 | CLKDIV << 3 | outputUpdateRate;



    r &= ~(1 << 2); // clear CLK



    //digitalWrite(pinCS, LOW);

    spiTransfer(r);

    //digitalWrite(pinCS, HIGH);

}



//Setup Register

//  7     6     5     4     3      2      1      0

//MD10) MD0(0) G2(0) G1(0) G0(0) B/U(0) BUF(0) FSYNC(1)



void AD770X::writeSetupRegister(byte operationMode, byte gain, byte unipolar, byte buffered, byte fsync) {

    byte r = operationMode << 6 | gain << 3 | unipolar << 2 | buffered << 1 | fsync;



    //digitalWrite(pinCS, LOW);

    spiTransfer(r);

    //digitalWrite(pinCS, HIGH);

}



unsigned int AD770X::readADResult() {

    //digitalWrite(pinCS, LOW);

    byte b1 = spiTransfer(0x0);

    byte b2 = spiTransfer(0x0);

    //digitalWrite(pinCS, HIGH);



    unsigned int r = b1 << 8 | b2;



    return r;

}



unsigned int AD770X::readADResultRaw(byte channel) {

    while (!dataReady(channel)) {

    };

    setNextOperation(REG_DATA, channel, 1);



    return readADResult();

}



double AD770X::readADResult(byte channel, float refOffset) {

    return readADResultRaw(channel) * 1.0 / 65536.0 * VRef - refOffset;

}



bool AD770X::dataReady(byte channel) {

    setNextOperation(REG_CMM, channel, 1);



    //digitalWrite(pinCS, LOW);

    byte b1 = spiTransfer(0x0);

    //digitalWrite(pinCS, HIGH);



    return (b1 & 0x80) == 0x0;

}



void AD770X::reset() {

    //digitalWrite(pinCS, LOW);

    /*for (int i = 0; i < 100; i++)

        spiTransfer(0xff);*/



    digitalWrite(0, LOW);

    delay(100);

    digitalWrite(0, HIGH);

    //digitalWrite(pinCS, HIGH);

}



AD770X::AD770X(double vref) {

    VRef = vref;

    pinMode(pinMOSI, OUTPUT);

    pinMode(pinMISO, INPUT);

    pinMode(pinSPIClock, OUTPUT);

    pinMode(pinCS, OUTPUT);

    pinMode(0, OUTPUT); // RST



    vspi.begin();//pinSPIClock, pinMISO, pinMOSI, pinCS);



    digitalWrite(pinCS, HIGH);

    //SPCR = _BV(SPE) | _BV(MSTR) | _BV(CPOL) | _BV(CPHA) | _BV(SPI2X) | _BV(SPR1) | _BV(SPR0);

}



void AD770X::init(byte channel, byte clkDivider, byte polarity, byte gain, byte updRate) {

    setNextOperation(REG_CLOCK, channel, 0);

    writeClockRegister(0, clkDivider, updRate);



    setNextOperation(REG_SETUP, channel, 0);

    writeSetupRegister(MODE_SELF_CAL, gain, polarity, 0, 0);



    while (!dataReady(channel)) {

    };

}



void AD770X::init(byte channel) {

    init(channel, CLK_DIV_1, BIPOLAR, GAIN_1, UPDATE_RATE_25);

}

.h file:

Code: AD7705.h Select all

#ifndef AD770X_H

#define AD770X_H



#include <Arduino.h>



#include <SPI.h>



/*

 * AD7705/AD7706 Library

 * Kerry D. Wong

 * http://www.kerrywong.com

 * Initial version 1.0 3/2011

 * Updated 1.1 4/2012

 */



//#define SPI_CLK 16000000UL // 16 MHz

#define SPI_CLK 400000UL // 400 kHz



class AD770X {

public:

    //register selection 

    //RS2 RS1 RS0

    static const byte REG_CMM = 0x0; //communication register 8 bit

    static const byte REG_SETUP = 0x1; //setup register 8 bit

    static const byte REG_CLOCK = 0x2; //clock register 8 bit

    static const byte REG_DATA = 0x3; //data register 16 bit, contains conversion result

    static const byte REG_TEST = 0x4; //test register 8 bit, POR 0x0

    static const byte REG_NOP = 0x5; //no operation

    static const byte REG_OFFSET = 0x6; //offset register 24 bit

    static const byte REG_GAIN = 0x7; // gain register 24 bit



    //channel selection for AD7706 (for AD7705 use the first two channel definitions)

    //CH1 CH0

    static const byte CHN_AIN1 = 0x0; //AIN1; calibration register pair 0

    static const byte CHN_AIN2 = 0x1; //AIN2; calibration register pair 1

    static const byte CHN_COMM = 0x2; //common; calibration register pair 0

    static const byte CHN_AIN3 = 0x3; //AIN3; calibration register pair 2



    //output update rate

    //CLK FS1 FS0

    static const byte UPDATE_RATE_20 = 0x0; // 20 Hz

    static const byte UPDATE_RATE_25 = 0x1; // 25 Hz

    static const byte UPDATE_RATE_100 = 0x2; // 100 Hz

    static const byte UPDATE_RATE_200 = 0x3; // 200 Hz

    static const byte UPDATE_RATE_50 = 0x4; // 50 Hz

    static const byte UPDATE_RATE_60 = 0x5; // 60 Hz

    static const byte UPDATE_RATE_250 = 0x6; // 250 Hz

    static const byte UPDATE_RATE_500 = 0x7; // 500 Hz



    //operating mode options

    //MD1 MD0

    static const byte MODE_NORMAL = 0x0; //normal mode

    static const byte MODE_SELF_CAL = 0x1; //self-calibration

    static const byte MODE_ZERO_SCALE_CAL = 0x2; //zero-scale system calibration, POR 0x1F4000, set FSYNC high before calibration, FSYNC low after calibration

    static const byte MODE_FULL_SCALE_CAL = 0x3; //full-scale system calibration, POR 0x5761AB, set FSYNC high before calibration, FSYNC low after calibration



    //gain setting

    static const byte GAIN_1 = 0x0;

    static const byte GAIN_2 = 0x1;

    static const byte GAIN_4 = 0x2;

    static const byte GAIN_8 = 0x3;

    static const byte GAIN_16 = 0x4;

    static const byte GAIN_32 = 0x5;

    static const byte GAIN_64 = 0x6;

    static const byte GAIN_128 = 0x7;



    static const byte UNIPOLAR = 0x0;

    static const byte BIPOLAR = 0x1;



    static const byte CLK_DIV_1 = 0x1;

    static const byte CLK_DIV_2 = 0x2;



    SPIClass vspi;





    byte spiTransfer(volatile byte data) {

        

        vspi.beginTransaction(SPISettings(SPI_CLK, MSBFIRST, SPI_MODE0));

        digitalWrite(pinCS, LOW);

        vspi.transfer(data);

        digitalWrite(pinCS, HIGH);

        vspi.endTransaction();





        return data;

    };



    AD770X(double vref);

    void setNextOperation(byte reg, byte channel, byte readWrite);

    void writeClockRegister(byte CLKDIS, byte CLKDIV, byte outputUpdateRate);

    void writeSetupRegister(byte operationMode, byte gain, byte unipolar, byte buffered, byte fsync);

    unsigned int readADResultRaw(byte channel);

    double readADResult(byte channel, float refOffset = 0.0);

    void reset();

    bool dataReady(byte channel);

    void init(byte channel);

    void init(byte channel, byte clkDivider, byte polarity, byte gain, byte updRate);

private:

    static const int pinMOSI = 23; //MOSI

    static const int pinMISO = 19; //MISO

    static const int pinSPIClock = 18; //SCK

    static const int pinCS = 5; //CS

    double VRef;

    unsigned int readADResult();

};

#endif

[jgustavoam]

Hi,
Let's do it by steps...
https://github.com/espressif/arduino-esp32

Important References:
https://docs.espressif.com/projects/esp ... aster.html (ESP-IDF only)
https://docs.espressif.com/projects/ard ... arted.html

See how to build an ESP32 Arduino library. I'm not an experienced programmer.
https://github.com/espressif/esp32-arduino-lib-builder

Searching for a ready-made library.
https://github.com/search?p=2&q=esp32+a ... positories

Ready-made Library BME280 (SPI), for example:
https://github.com/mgo-tec/ESP32_BME280_SPI
https://www.bosch-sensortec.com/media/b ... -ds002.pdf

https://github.com/espressif/arduino-es ... _Buses.ino

Code: Select all

/* The ESP32 has four SPi buses, however as of right now only two of
 * them are available to use, HSPI and VSPI. Simply using the SPI API 
 * as illustrated in Arduino examples will use VSPI, leaving HSPI unused.
 * 
 * However if we simply intialise two instance of the SPI class for both
 * of these buses both can be used. However when just using these the Arduino
 * way only will actually be outputting at a time.

----------------------------------------------------------------------

Do you know the Golang language? Very simple.
https://tinygo.org/docs/reference/micro ... eboard-v2/
https://github.com/Gustavomurta/tinyGo_ ... 04/main.go