The Factory Information Configuration Registers (FICR) are stored in the One Time Programmable (OTP) memory.
FICR has two regions:
- A factory-programmed region that contains device information and has the INFO group registers.
- A customer-programmable region that contains empty registers for the customer to write data to. It has the QSPI, MAC, and CALIB group registers.
Access to the customer-programmable region is controlled using the PROTECTION register.
The PROTECTION scenarios are:
- When PROTECTION is unprogrammed, neither read not write is enabled.
- When PROTECTION is programmed to 0x50FA50FA, full read and write access is enabled.
- When PROTECTION is programmed to 0x00000000, access protection is applied and readout of QSPI.KEY is prevented.
The following table shows the access protection for the different register groups.
| Register group | 0xFFFFFFFF | 0x50FA50FA | 0x00000000 |
|---|---|---|---|
| QSPI.KEY | - | R/W | - |
| MAC.ADDRESS | - | R/W | R |
| CALIB | - | R/W | R |