The AT24CSW04X/AT24CSW08X includes a 32-byte Security register. The Security register is segmented into a 16-byte read-only section and a 16‑byte user-programmable section organized as 2 pages of 16 bytes each. The user-programmable portion supports both byte write and page write operations. The read-only section contains a preprogrammed ensured unique 128-bit serial number. The user-programmable portion may be permanently locked at any time with the Lock command.
| Security Register Byte Number | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 0 | 1 | ... | 14 | 15 | 16 | 17 | ... | 30 | 31 |
| Factory-Programmed (Read-only) 0-15: Device Serial Number |
User-Programmable (Lockable) | ||||||||