C8051F93X Datasheet, PDF (151/330 Pages) Silicon Laboratories – Pipelined intstruction architecture executes 70 of instruction in 1 or 2 system clocks

C8051F93x-C8051F92x
The level of Flash security depends on the Flash access method. The three Flash access methods that
can be restricted are reads, writes, and erases from the C2 debug interface, user firmware executing on
unlocked pages, and user firmware executing on locked pages. Table 13.1 summarizes the Flash security
features of the C8051F93x-C8051F92x devices.
Table 13.1. Flash Security Summary
Action
C2 Debug User Firmware executing from:
Interface
an unlocked page a 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
FEDR
Permitted
Read or Write page containing Lock Byte
(if no pages are locked)
Permitted
Permitted
Permitted
Read or Write page containing Lock Byte
(if any page is locked)
Not Permitted
FEDR
Permitted
Read contents of Lock Byte
(if no pages are locked)
Permitted
Permitted
Permitted
Read contents of Lock Byte
(if any page is locked)
Not Permitted
FEDR
Permitted
Erase page containing Lock Byte
(if no pages are locked)
Permitted
FEDR
FEDR
Erase page containing Lock Byte - Unlock all pages Only by C2DE
(if any page is locked)
FEDR
FEDR
Lock additional pages
(change 1s to 0s in the Lock Byte)
Not Permitted
FEDR
FEDR
Unlock individual pages
(change 0s to 1s in the Lock Byte)
Not Permitted
FEDR
FEDR
Read, Write or Erase Reserved Area
Not Permitted
FEDR
FEDR

C2DE—C2 Device Erase (Erases all Flash pages including the page containing the Lock Byte)
FEDR—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.
- The scratchpad is locked when all other Flash pages are locked.
- The scratchpad is erased when a Flash Device Erase command is performed.
Rev. 1.3
151