The AT24CSW04X is internally organized as 32 pages of 16 bytes each and the AT24CSW08X is organized as 64 pages of 16 bytes each for the EEPROM array. The device also contains a 32‑byte Security Register which is organized as two pages of 16 bytes each. This register contains a factory-programmed ensured unique 128‑bit serial number in the lower 16 bytes. The upper 16 bytes are user‑programmable and can (later) be permanently write‑protected (see Security Register).
Figure 1. Memory Organization
The AT24CSW04X/AT24CSW08X also contains an 8‑bit Write Protection register that controls which regions of the memory can be written to. Details about how to use this register can be found in Write Protection.