due_hash.cpp

bool flash_read_unique_id(uint32_t *pul_data) {
  // Initialize the first EEFC bank in 128-bit mode with 4 wait states
  if (efc_init(EFC0, 0, 4)) {
    return false;
  }

  // Enter the unique identifier mode, copy it, and exit
  return !efc_perform_read_sequence(EFC0, EFC_FCMD_STUI, EFC_FCMD_SPUI, pul_data, 4);
}

void setup() {
  SerialUSB.begin(115200);
}

void loop() {
  uint32_t unique_id[4];
  if (flash_read_unique_id(unique_id)) {
    uint32_t hash = unique_id[0] ^ unique_id[1] ^ unique_id[2] ^ unique_id[3];
    SerialUSB.println(hash, HEX);
  }

  delay(1000);
}