29.4.8 Unique Identifier Area

Each device is programmed with a 4-Kbyte unique identifier area. See Figure 29-1.

The sequence to read the unique identifier area is the following:

  1. Perform a dummy read at the Flash base address. Execute the ‘Start Read Unique Identifier’ command by writing EEFC_FCR.FCMD with the STUI command. EEFC_FCR.FARG is meaningless.
  2. Wait until the bit EEFC_FSR.FRDY falls to read the unique identifier area. The unique identifier field is located in the first 128 bits of the Flash memory mapping. The ‘Start Read Unique Identifier’ command reuses some addresses of the main memory plane for code, but the unique identifier area is physically different from the main memory plane for code.
  3. To stop reading the unique identifier area, execute the ‘Stop Read Unique Identifier’ command by writing EEFC_FCR.FCMD with the SPUI command. Field EEFC_FCR.FARG is meaningless.
  4. When the SPUI command has been executed, EEFC_FSR.FRDY rises. If an interrupt was enabled by setting EEFC_FMR.FRDY, the interrupt line of the interrupt controller is activated.

Note that during the sequence, the software cannot be fetched from the Flash.