SLOA208B November 2014 – March 2019 TRF7970A , TRF7970A
This structure defines the parameters for each individual file within the specified application (see Figure 8). It contains the following four parameters:
The file ID for the CC file must be set to 0xE103 to be in compliance with the NFC Forum specifications. All other files must use values that are not reserved for use by the NFC Forum. See the NFC Forum Type 4 Tag Operation Specification 3.0 for details on the available file ID numbers.
The read/write privileges of the file must match the privileges set inside of the capability container file. The write privilege values between the CC and the tType4File structure are independent of each other. A mismatch between the values could lead to unintentional file updates.
It is important to ensure that the write privileges are correctly set for code that is loaded into flash memory. If the write privileges are not disabled then writers such as handsets may attempt to overwrite the tag data.
The bReadOnly flag is also useful to ensure that tag data can be modified only by the application. For example, if an application is measuring a value such as temperature and updating the tag with that information then using the bReadOnly would prevent a handset from accidently overwriting the measurement.