ADS1256 Reading register code snippet

//This is the function which reads the value of a selected register
//The function expects the address of the register and returns with its value
//The code belongs to the following Youtube tutorial: https://youtu.be/KQ0nWjM-MtI
//If you used the code, please SUBSCRIBE: https://www.youtube.com/c/CuriousScientist
/*
If you want to buy the parts and support me at the same time, please use the following affiliation links:
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ADS1256 Board (green): https://www.banggood.com/custlink/Dmv3VZHrDC
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*/
//Datasheet: http://www.ti.com/lit/ds/sbas288k/sbas288k.pdf

unsigned long readRegister(uint8_t registerAddress) //Function for READING a selected register
{
    waitforDRDY(); //Waiting for DRDY to go low ('1')
    //this is a separate function that watches the attachinterrupt() pin

    SPI.beginTransaction(SPISettings(1700000, MSBFIRST, SPI_MODE1));
    //SPI_MODE1 = output edge: rising, data capture: falling; clock polarity: 0, clock phase: 1.

    digitalWrite(CS_pin, LOW); //CS must stay LOW during the entire sequence [Ref: P34, T24]

    delayMicroseconds(7); //see t6 in the datasheet
    //t6 = 50 * tau_CLKIN = 50 * 130.2 ns = 6510 ns = 6.51 us; you want to round it UP to the next integer (even if it would be 6.1 us)

    SPI.transfer(0x10 | registerAddress); //0x10 = RREG, '|' = bitwise OR operation

    SPI.transfer(0x00);

    delayMicroseconds(7); //see t6 in the datasheet

    registerValueR = SPI.transfer(0xFF); //obtaining the data and 'saving' into the variable

    delayMicroseconds(7); //see t6 in the datasheet

    digitalWrite(CS_pin, HIGH);

    SPI.endTransaction();

    return registerValueR;
}