How does NFC rewrite code?

[Schuyler]

Why do I rewrite the code according to the example of nfc07a1, but the string of smartag is always read out? Can I change its code?

void MX_NFC7_NDEF_URI_Init(void){
   SmarTag_LED_GREEN_On();
	while( SMARTAG1_NFCTAG_Init(SMARTAG1_NFCTAG_INSTANCE) != NFCTAG_OK ){}
    /* Reset Mailbox enable to allow write to EEPROM */
  SMARTAG1_NFCTAG_ResetMBEN_Dyn(SMARTAG1_NFCTAG_INSTANCE);
 /* Check if no NDEF detected, init mem in Tag Type 5 */
  if( NfcType5_NDEFDetection( ) != NDEF_OK ) {
    CCFileStruct.MagicNumber = NFCT5_MAGICNUMBER_E1_CCFILE;
    CCFileStruct.Version = NFCT5_VERSION_V1_0;
    CCFileStruct.MemorySize = ( ST25DV_MAX_SIZE / 8 ) & 0xFF;
    CCFileStruct.TT5Tag = 0x05;
    while( NfcType5_TT5Init( ) != NFCTAG_OK ) ;
    
  }

        SmarTag_LED_GREEN_Off();
}


/**
  * @brief  Process of the NDEF_URI application
  * @retval None
  */
void MX_NFC7_NDEF_URI_Process(void)
{

      char str[] = "Hello, NFC!";
      const uint16_t size = strlen(str) + 1;
      NfcType5_WriteNDEF(size, (uint8_t *)str);
	  HAL_Delay(300);
}

[Rene Lenerve · Accepted solution]

Hi Schuyler,

First point take care that NFC07 is based on ST25DVKC and smartag1 is based on ST25DVK, they are very similar but IC Ref information and some registers are not at same address.

See DataSheet:

ST25DV64KC

ST25DV64K

Second point, you may check if the memory address is not protected by password for write on I²C side.

Getting more information about what was wrong (error code returned, line of code where something goes wrong, ..) would help to precise what went wrong.

If you want to write raw data it would be preferable not to use writeNDEF functions as it is intended to write formated data as NDEF.

Kind Regards.