brp_Iso14a_RequestATS()

brp_errcode brp_Iso14a_RequestATS	(	brp_protocol	protocol,
		brp_Iso14a_RequestATS_FSDI	FSDI,
		unsigned	CID,
		brp_buf *	ATS,
		size_t *	ATS_len,
		brp_mempool *	mempool
	)

This command requests the Answer to Select (ATS) of the PICC according to the ISO 14443-3 (Type A) standard.

RequestATS has to be called by the PCD (reader) directly after a successful call of the brp_Iso14a_Select() command if

1. The selected PICC is ISO 14443-4 compliant (according to SAK byte) and
2. communication as specified by ISO 14443-4 shall be performed via the brp_Iso14L4_ExchangeAPDU() command.

Since it is possible to keep several PICCs in active state at the same time according to ISO 14443-4, a unique CID has to be assigned to each of them. However, if you only want to communicate with a single label at a given time, the value 0 should be assigned to the CID variable. In this case, it is possible to call the brp_Iso14L4_ExchangeAPDU() command without bothering about CIDs.

Please refer to the brp_Iso14a_PerformPPS() and brp_Iso14L4_ExchangeAPDU() command descriptions for more information about frame sizes and timing issues.

After successful execution of this command, the communication parameters can be tuned with the brp_Iso14a_PerformPPS() command.

Parameters

[in]	protocol	used to execute the command
[in]	FSDI	Frame Size proximity coupling Device Integer (FSDI) value. This value is mapped to the Frame Size proximity coupling Device (FSD) value, which indicates the maximum frame size accepted by the PCD. The current Baltech reader supports FSD of at least up to 64 bytes (FSDI=0x05). It is not recommended to use a smaller FSDI. Future versions of the Baltech reader might support higher FSDI values.
[in]	CID	Channel ID which shall be assigned to this PICC. Possible values: * 0x00: PICC will also respond to ISO 14443-4 commands with CID disabled. * 0x01-0x0E: valid CID value. * 0x0F-0xFF: rfu.
[out]	ATS	Answer To Selection (ATS) of the PICC. This field has a variable length up to 32 Bytes according to the ISO 14443-4 standard.
[out]	ATS_len
[in]	mempool	is used to store response data. Maybe NULL to use an internal mempool, in this case the data is only available until another command uses the internal mempool