No meaningful data being read from the ADC register output of the CN0540 using a Teensy 4.1

Picture and Teensy code are attached. Yes; I am bit shifting and reading thrice to get the final result. I am using a Kingst LA1010 Logic Analyzer to probe the pins and using in-built Arduino-SPI commands in the code. For the bench setup, I just shake the CN0532 board to check if the output graphical values indicate the right movements. When I do a similar test with the DE-10 (CN0549) setup, this sanity check indicates that the readings are matching up to the accelerometer movements.

// the sensor communicates using SPI, so include the library:
#include <SPI.h>
#include <SD.h>
#include <avr/io.h>
#include <avr/interrupt.h>

const int CardSelect = BUILTIN_SDCARD;
//Sensor's memory register addresses:
const int CHIP_TYPE = 0x03;      //8 bit value and reset is 7
const int PRODUCTID = 0x04;  //8 bit and reset is 1
const int POWER_CLOCK = 0x15;   //8 bit and reset is 0
const int ADC_DATA = 0x2C;   //24 bit conversion result
const byte READ = 0b01000000;     // AD7768's read command
const byte WRITE = 0b00000000;   // AD7768's write command
String tempString;

// pins used for the connection with the sensor
// the other you need are controlled by the SPI library):
const int dataReadyPin = 2;
const int chipSelectPin = 10;
const int button = 4;

void setup() {
  Serial.begin(115200);
  // start the SPI library:
  SPI.begin();

  // initalize the  data ready and chip select pins
  pinMode(dataReadyPin, INPUT);
  pinMode(chipSelectPin, OUTPUT);
  pinMode(3, OUTPUT);
 
  digitalWrite (chipSelectPin, HIGH);
  digitalWrite (11, HIGH);

  digitalWrite (3, LOW);
  delayMicroseconds (20);
  digitalWrite (3, HIGH);
  
  attachInterrupt(digitalPinToInterrupt(2), blink, CHANGE);
  //attachInterrupt(digitalPinToInterrupt(4), press (myFile), CHANGE);

}

void loop() {
}

//Read from or write to register from the SCP1000:
unsigned int readRegister(byte thisRegister, int bytesToRead ) {
  byte inByte = 0;
 
  digitalWrite (11, HIGH);
  // gain control of the SPI port
  // and configure settings
  SPI.beginTransaction(SPISettings(4000000, MSBFIRST, SPI_MODE3));
  
  // take the chip select low to select the device:
  digitalWrite(chipSelectPin, LOW);

  int result = SPI.transfer(0x00);
  bytesToRead--;
  // if you still have another byte to read:
  while (bytesToRead > 0) {
    // shift the first byte left, then get the second byte:
    result = result << 8;
    inByte = SPI.transfer(0x00);
  
    // combine the byte you just got with the previous one:
    result = result | inByte;
    // decrement the number of bytes left to read:
    bytesToRead--;
    
  }
  

 Serial.println(result);
 
 // take the chip select high to de-select:
  digitalWrite(chipSelectPin, HIGH);
 
 // release control of the SPI port
  SPI.endTransaction();
  
 digitalWrite (3, LOW);
 delayMicroseconds (20);
 digitalWrite (3, HIGH);
}


//Sends a write command to SCP1000

void writeRegister(byte thisRegister, byte thisValue) {

  byte dataToSend = thisRegister | WRITE;

  // gain control of the SPI port
  // and configure settings
  SPI.beginTransaction(SPISettings(24000000, MSBFIRST, SPI_MODE3));
  // take the chip select low to select the device:
  digitalWrite(chipSelectPin, LOW);

  SPI.transfer(dataToSend); //Send register location
  SPI.transfer(thisValue);  //Send value to record into register

  // take the chip select high to de-select:
  digitalWrite(chipSelectPin, HIGH);
  // release control of the SPI port
  SPI.endTransaction();
}

void blink() {
  readRegister(0x2C,3);

}

int press(File myFile) {
  myFile.close();
}

Can we have a chat sometime? I still don't have any luck getting meaningful data out. Turns out the DE-10 system does not allow any of the registers to be configured (so it can only be used in the default settings). Also, there is a mismatch between the pinouts in the schematic and the ones marked on the board for block P8 of the CN0540. I need to understand if I am better off using another product line. Is the CN0540 a beta release?

Hi Girjia,

I checked your code and I noticed that there is no part where a GPIO drives the ADG5421 IN1 and IN2 pins. You need to drive this pins (specifically SHUTDOWN in P3 pin 9 and SW_CC  in P5 pin 7 of the Arduino headers) for the board to power and sample from the IEPE sensor.