Several lock bits are used to protect write and erase operations on lock regions. A lock region is composed of several consecutive pages, and each lock region has its associated lock bit.
| Flash Size (Kbytes) | Number of Lock Bits | Lock Region Size |
|---|---|---|
| 2048 | 128 | 16 Kbytes |
| 1024 | 64 | 16 Kbytes |
| 512 | 32 | 16 Kbytes |
Asserting the ERASE pin clears the lock bits, thus unlocking the entire Flash.