ADS124S08: Device Ready Flag (!RDY) high after RESET command

Tool/software:

Hi,
I'm following the pseudo-code example from the datasheet (10.1.6, pg. 90)


but when I send the RESET command and then read the status register (using the RREG command) to check the device ready flag it always comes back as 1.

Before sending the RESET command it was 0 (as it should be). I've tried with bigger delays and/or different SPI speeds but it is always the same result.
I've also tried other libraries and the result is the same.

I don't know if I'm misunderstanding something or if I'm doing something wrong.

Here is the code

library:

// C++
#include "PUADS124S08.h"

void PUADS124S08::deselect()
{
  digitalWrite(cs, HIGH);
  SPI.endTransaction();
  // Wait >~20ns
  asm (
    "nop" "\n"
    "nop" "\n"
    "nop" "\n"
    "nop" "\n"
    "nop" "\n"
    "nop" "\n"
    "nop" "\n"
    "nop" "\n"
    "nop" "\n"
  );
}

void PUADS124S08::select()
{
  SPI.beginTransaction(spisett);
  digitalWrite(cs, LOW);
  // TODO: Wait 4096 * (1 / freq)
  asm (
    "nop" "\n"
    "nop" "\n"
    "nop" "\n"
    "nop" "\n"
    "nop" "\n"
    "nop" "\n"
    "nop" "\n"
    "nop" "\n"
    "nop" "\n"
  );
}

PUADS124S08::PUADS124S08(int cs) : cs(cs)
{
  pinMode(cs, OUTPUT);
  deselect();
}

bool PUADS124S08::reset()
{
  select();
  SPI.transfer(Commands::RESET);
  deselect();

  delayMicroseconds(100);
  if (!isready())
  {
    return false;
  }
  // TODO: FL_POR flag
  return true;
}

bool PUADS124S08::isready()
{
  uint8_t byte = readb(Registers::STATUS);

  #ifdef DEBUG
  Serial.println(millis());
  Serial.print("Status register: ");
  Serial.print("0b");
  Serial.print(byte, BIN);
  Serial.println();
  #endif

  return !(byte & 0b01000000);
}

uint8_t PUADS124S08::readb(uint8_t adrr)
{
  uint8_t com = Commands::RREG | (adrr & 0b00011111);
  uint8_t r;
  select();
  SPI.transfer(com);
  SPI.transfer(0x00);
  r = SPI.transfer(0x00);
  deselect();
  return r;
}

main:

(codeblock not working)

```cpp
// main.cpp
#include <Arduino.h>
#include <PUADS124S08.h>

#define MISO 16
#define MOSI 19

PUADS124S08 adc1;

void setup() {
  delay(3000);
  pinMode(MISO, INPUT);
  pinMode(MOSI, OUTPUT);

  Serial.begin(115200);
  SPI.begin();
 
  adc1 = PUADS124S08(15);
  Serial.println(adc1.isready());

  // adc1.reset();
  while (!adc1.reset())
  {
    Serial.println("Error");
    delay(1000);
  }
  Serial.println("ADC Init");
  while(1);
}
```

// main.cpp
#include <Arduino.h>
#include <PUADS124S08.h>

#define MISO 16
#define MOSI 19

PUADS124S08 adc1;

void setup() {
  delay(3000);
  pinMode(MISO, INPUT);
  pinMode(MOSI, OUTPUT);

  Serial.begin(115200);
  SPI.begin();
  
  adc1 = PUADS124S08(15);
  Serial.println(adc1.isready());

  // adc1.reset();
  while (!adc1.reset())
  {
    Serial.println("Error");
    delay(1000);
  }
  Serial.println("ADC Init");
  while(1);
}

serial:

740063
Status register: 0b11000000
Error
...
740231
Status register: 0b11000000
Error

Logic Analyzer

RESET:

RREG:

then I send 0x00

and 0x00 again to read the MISO:

Electric diagram:

Also I'm using a raspberry pi pico (rp2040) with the Arduino framework

Any help would be greatly appreciated

Thanks