C8051F850-C-GM Datasheet, PDF (68/328 Pages) Silicon Laboratories – Low-Cost 8-bit MCU Family with up to 8 kB of Flash

Table 10.1. Flash Security Summary (Continued)
Read contents of Lock Byte
(if no pages are locked)
Read contents of Lock Byte
(if any page is locked)
Erase page containing Lock Byte
(if no pages are locked)
Erase page containing Lock Byte—Unlock all
pages (if any page is locked)
Lock additional pages
(change 1s to 0s in the Lock Byte)
Unlock individual pages
(change 0s to 1s in the Lock Byte)
Read, Write or Erase Reserved Area
Permitted
Permitted
Not Permitted Flash Error Reset
Permitted
Permitted
C2 Device Erase
Only
Not Permitted
Flash Error Reset
Flash Error Reset
Not Permitted Flash Error Reset
Not Permitted Flash Error Reset
N/A
Permitted
N/A
Flash Error Reset
Flash Error Reset
Flash Error Reset
Flash Error Reset
C2 Device Erase—Erases all flash pages including the page containing the Lock Byte.
Flash Error Reset —Not permitted; Causes Flash Error Device Reset (FERROR bit in RSTSRC is '1' after reset).
- All prohibited operations that are performed via the C2 interface are ignored (do not cause device reset).
- Locking any flash page also locks the page containing the Lock Byte.
- Once written to, the Lock Byte cannot be modified except by performing a C2 Device Erase.
- If user code writes to the Lock Byte, the Lock does not take effect until the next device reset.
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Rev. 1.0