7.5.1 Permanent Software Write Protection (PSWP)

The Permanent Software Write Protection (PSWP) is enabled by sending a command to the device, similar to a normal write operation, which programs the Permanent Write-Protect register. This must be done with the WP pin low. The Write‑Protect register is programmed by sending a write command with the device type identifier of ‘0110’ (6h) instead of ‘1010’ (Ah) with the address and data bit(s) being don’t cares. The write cycle time must be observed. Once the PSWP has been enabled, the device will no longer acknowledge the ‘0110’ (6h) device type identifier and cannot be reversed even if the device is powered down.