SLOA208B November 2014 – March 2019 TRF7970A , TRF7970A
To read the data from an emulated Type 4 tag an NFC reader/writer must first select an application within the tag and then select the files within the application by using the Select command.
To select an application the ID number of application must be sent by the NFC reader/writer. If the ID number matches an application contained within the tag then a R-PDU is sent back in reply to confirm the selection of the file. If the ID number does not match an error code 0x6A82 is sent back instead to inform the device the application it requested was not found.
A file can only be selected by an NFC reader/writer after an application has been selected. The process to select a file is the same as selecting an application. The file ID number must be sent, and if file with that ID is in the application, a reply is sent to confirm the selection. Otherwise, the error code 0x6A82 is sent back. All NFC devices should search for the CC file first (file ID = 0xE103) to get the information about all of the other files available within the application.
The firmware only supports two Select commands; by name and by file identifier.
When using the Select command, the Lc byte shall be set to the length of the application or file ID number, and the Data Bytes shall contain the ID number itself. The Le byte shall not be included.