The current version of the NFC Type 2 Tag library supports only one Type 2 Tag command type: the READ command. When a READ command is received, the tag responds with the data that is stored for the tag.

READ command format

The READ command has the following format:

Byte number	Description	Value
1	Code	0x30
2	Number of the 4-byte data block to read from the tag data	0x00 - 0xFF

The library can send either a READ response (success) or a NACK response (failure):

A READ response contains the content of 4 data blocks starting with the requested data block (16 bytes).
A NACK response contains the error code 0x0, 0x1, 0x4, or 0x5 (4 bits).