C8051F970-A-GM Datasheet, PDF (66/454 Pages) Silicon Laboratories – Low Power Capacitive Sensing MCU with up to 32 kB of Flash

C8051F97x
Table 10.1. Flash Security Summary
Action
C2 Debug Interface
User Firmware Executing from:
Unlocked Page
Locked Page
Read, Write or Erase unlocked pages
(except page with Lock Byte)
Permitted
Permitted
Permitted
Read, Write or Erase locked pages
(except page with Lock Byte)
Not Permitted
Flash Error Reset
Permitted
Read or Write page containing Lock Byte
(if no pages are locked)
Read or Write page containing Lock Byte
(if any page is locked)
Permitted
Not Permitted
Permitted
Flash Error Reset
N/A
Permitted
Read contents of Lock Byte
(if no pages are locked)
Permitted
Permitted
N/A
Read contents of Lock Byte
(if any page is locked)
Erase page containing Lock Byte
(if no pages are locked)
Not Permitted
Permitted
Flash Error Reset
Permitted
Permitted
N/A
Erase page containing Lock Byte—Unlock all C2 Device Erase Only
pages (if any page is locked)
Lock additional pages
(change 1s to 0s in the Lock Byte)
Not Permitted
Unlock individual pages
(change 0s to 1s in the Lock Byte)
Not Permitted
Flash Error Reset
Flash Error Reset
Flash Error Reset
Flash Error Reset
Flash Error Reset
Flash Error Reset
Read, Write or Erase Reserved Area
Not Permitted
Flash Error Reset Flash Error Reset
Notes:
1. C2 Device Erase erases all flash pages including the page containing the Lock Byte.
2. Flash Error Reset is not permitted; Causes Flash Error Device Reset (FERROR bit in RSTSRC is “1” after reset).
3. All prohibited operations that are performed via the C2 interface are ignored (do not cause device reset).
4. Locking any flash page also locks the page containing the Lock Byte.
5. Once written to, the Lock Byte cannot be modified except by performing a C2 Device Erase.
6. If user code writes to the Lock Byte, the Lock does not take effect until the next device reset.
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