20.3.1 Non-Volatile Memory Lock Bits
The device provides two Lock Bits.
| Lock Bit Byte | Bit No. | Description | Default Value |
|---|---|---|---|
| 7 | 1 (unprogrammed) | ||
| 6 | 1 (unprogrammed) | ||
| 5 | 1 (unprogrammed) | ||
| 4 | 1 (unprogrammed) | ||
| 3 | 1 (unprogrammed) | ||
| 2 | 1 (unprogrammed) | ||
| NVLB2 | 1 | Non-Volatile Lock Bit | 1 (unprogrammed) |
| NVLB1 | 0 | Non-Volatile Lock Bit | 1 (unprogrammed) |
The Lock Bits can be left unprogrammed ("1") or can be programmed ("0") to obtain the additional security. Lock Bits can be erased to "1" with the Chip Erase command, only.
| Memory Lock Bits(1) | Protection Type | ||
|---|---|---|---|
| LB Mode | NVLB2(2) | NVLB1(2) | |
| 1 | 1 | 1 | No memory lock features enabled. |
| 2 | 1 | 0 | Further Programming of the Flash memory is disabled in the external programming mode. The configuration section bits are locked in the external programming mode |
| 3 | 0 | 0 | Further programming and verification of the flash is disabled in the external programming mode. The configuration section bits are locked in the external programming mode |
Note:
- Program the configuration section bits before programming NVLB1 and NVLB2.
- "1" means unprogrammed, "0" means programmed