What is the antenna range of the NXP EXPLORE-NFC expansion board?

Dear friends.

I am  write a C library using SPI communication for interface the Board NFC EXPLORE PN512 with a micocrontroller 8 bit, 16 bit or 32 bit. This because lot off pleople dont has Raspeberry or prefere use this Board with another MCU, like in my case.

After one week working in this projects I can manager the NFC EXPLORE register, for exemaple write and read the FIFO BUFFER, clear the configuration, transmitte data to RF anntena.

Now I need any help to solve the last problem that is: Cannot send data to MIFARE card to read the UID or other data that is store in the card EEPROM.

Below is my code:

// THIS LINES OF CODE CONFIGURE THE DEVICE TO ENABLE RF ANTENA AND

EXPLORE_NFC_PN512_ControlReg(0x05);

  EXPLORE_NFC_PN512_TxAutoReg();

  EXPLORE_NFC_PN512_RxThresholdReg();

  EXPLORE_NFC_PN512_RFCfgReg();

  EXPLORE_NFC_PN512_GsNOnReg();

  EXPLORE_NFC_PN512_TxControlReg();

  // CLEAR THE FIFO BUFFER BEFORE  WRITE THE COMMAND DO BE SEND TO RF

  EXPLORE_NFC_PN512_Clear_Fifo_Buffer();

  EXPLORE_NFC_PN512_WRITE_MB_INTO_FIFO_BUFFER(0x26);  // value write 0x26h command do quest card

// NOW SEND THE FIFO CONTENT TO ANNTENA AND WAIT FOR MIFARE CARD RESPONSE

// IN THIS PARTICULAR CASE I WAITING FOR 04h 00h

EXPLORE_NFC_PN512_Start_Send();

EXPLORE_NFC_PN512_Transmit();

EXPLORE_NFC_PN512_Transceive();

    _delay_cycles (50000);

    nBytes=EXPLORE_NFC_PN512_GetFifoLevel(); // Get FiFo level

  _delay_cycles (50000);

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