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Topic: ADS1299 and Arduino SPI connection (Read 821 times) previous topic - next topic


I'm trying to transfer signals from ADS1299EEGFE to Arduino Uno board with SPI interface. I connected DRDY, CS, SCLK, Din, Dout and RESET pins to Arduino board. Also, I powered ADS1299 board with Arduino. For transferring data, I used a bi-directional level shifter between ADS1299 and Arduino. First of all, I just want to read device ID but I can't. Would you please help me with that? I get some data each time I run my code but they are wrong.


No wiring diagram, no code, no output from that code. How do you think should we help you if you don't provide the necessary information?


My code is here I just want to read Device ID:

#include "ADS1299.h"

ADS1299 ADS;
int count = 0;                         

void setup() {
  ADS.initialize(8,9,10,4,false); // (DRDY pin, RST pin, CS pin, SCK frequency in MHz);

  Serial.println("ADS1299-Arduino UNO Example 2");

  ADS.verbose = true;      // when verbose is true, there will be Serial feedback
  ADS.RESET();             // send RESET command to default all registers
  ADS.SDATAC();           // exit Read Data Continuous mode to communicate with ADS
} // end of setup

void loop(){

#include "pins_arduino.h"
#include "ADS1299.h"

void ADS1299::initialize(int _DRDY, int _RST, int _CS, int _FREQ, boolean _isDaisy){
   isDaisy = _isDaisy;
   DRDY = _DRDY;
   CS = _CS;
   int FREQ = _FREQ;
   int RST = _RST;
   delay(50);            // recommended power up sequence requiers Tpor (~32mS)   
   delayMicroseconds(4);   // toggle reset pin
   delayMicroseconds(20);   // recommended to wait 18 Tclk before using device (~8uS);

    // **** ----- SPI Setup ----- **** //
    // Set direction register for SCK and MOSI pin.
    // MISO pin automatically overrides to INPUT.
    // When the SS pin is set as OUTPUT, it can be used as
    // a general purpose output port (it doesn't influence
    // SPI operations).
    pinMode(13, OUTPUT);   //SCK
    pinMode(11, OUTPUT);   //MOSI
    pinMode(10, OUTPUT);   //CS
    digitalWrite(13, LOW);
    digitalWrite(11, LOW);
    digitalWrite(10, HIGH);
    // set as master and enable SPI
    SPCR |= _BV(MSTR);
    SPCR |= _BV(SPE);
    //set bit order
    SPCR &= ~(_BV(DORD)); ////SPI data format is MSB (pg. 25)
     // set data mode
    SPCR = (SPCR & ~SPI_MODE_MASK) | SPI_DATA_MODE; //clock polarity = 0; clock phase = 1 (pg. 8)
    // set clock divider
     switch (FREQ){
        case 8:
           DIVIDER = SPI_CLOCK_DIV_2;
        case 4:
           DIVIDER = SPI_CLOCK_DIV_4;
        case 1:
           DIVIDER = SPI_CLOCK_DIV_16;
    SPCR = (SPCR & ~SPI_CLOCK_MASK) | (DIVIDER);  // set SCK frequency 
    SPSR = (SPSR & ~SPI_2XCLOCK_MASK) | (DIVIDER); // by dividing 16MHz system clock 
    // **** ----- End of SPI Setup ----- **** //
    // initalize the  data ready chip select and reset pins:
    pinMode(8, INPUT);


//System Commands
void ADS1299::WAKEUP() {
    digitalWrite(CS, LOW);
    digitalWrite(CS, HIGH);
    delayMicroseconds(3);      //must wait 4 tCLK cycles before sending another command (Datasheet, pg. 35)

void ADS1299::STANDBY() {   // only allowed to send WAKEUP after sending STANDBY
    digitalWrite(CS, LOW);
    digitalWrite(CS, HIGH);

void ADS1299::RESET() {     // reset all the registers to default settings
    digitalWrite(CS, LOW);
    delayMicroseconds(12);    //must wait 18 tCLK cycles to execute this command (Datasheet, pg. 35)
    digitalWrite(CS, HIGH);

void ADS1299::START() {     //start data conversion
    digitalWrite(CS, LOW);
    digitalWrite(CS, HIGH);

void ADS1299::STOP() {      //stop data conversion
    digitalWrite(CS, LOW);
    digitalWrite(CS, HIGH);

void ADS1299::RDATAC() {
    digitalWrite(CS, LOW);
    digitalWrite(CS, HIGH);
void ADS1299::SDATAC() {
    digitalWrite(CS, LOW);
    digitalWrite(CS, HIGH);
  delayMicroseconds(3);   //must wait 4 tCLK cycles after executing this command (Datasheet, pg. 37)

byte ADS1299::RREG(byte _address) {      //  reads ONE register at _address
    byte opcode1 = _address + 0x20;    //  RREG expects 001rrrrr where rrrrr = _address
    digitalWrite(CS, LOW);    //  open SPI
    transfer(opcode1);            //  opcode1
    transfer(0x00);                //  opcode2
    regData[_address] = transfer(0x00);//  update mirror location with returned byte
    digitalWrite(CS, HIGH);          //  close SPI   
     if (verbose){                  //  verbose output
        Serial.print("ID :");
        Serial.print(", ");
        Serial.print(", ");
        for(byte j = 0; j<8; j++){
           Serial.print(bitRead(regData[_address], 7-j));
           if(j!=7) Serial.print(", ");
     return regData[_address];         // return requested register value

//SPI communication methods
byte ADS1299::transfer(byte _data) {
  SPDR = _data;
  while (!(SPSR & _BV(SPIF)));
  return SPDR;

// Used for printing HEX in verbose feedback mode
void ADS1299::printHex(byte _data){
    if(_data < 0x10) Serial.print("0");
    Serial.print(_data, HEX);

My output is random actually.

My wiring:

  SCK = 13
  MISO [DOUT] = 12
  MOSI [DIN] = 11
  CS = 10;
  RESET = 9;
  DRDY = 8;


First: use code tags (the </> button in the editor) when you post code!!

I'm surprised that you get any output than the greeting string with this code, because it doesn't read any value from the chip.

Is it possible that you didn't configure your serial monitor to the unnecessary high baud rate of 115200?

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