6
6-9
INTERNAL MEMORY
32182 Group User’s Manual (Rev.1.0)
FPROT = 0
FENTRY = 1
YES
NO
FENTRY = 1
FPROT = 1
FPROT is not set to 1 if a write cycle
to any other area occurs during this time.
FPR
O
T
=
0
FPR
O
T
=
1
Figure 6.4.1 Protection Unlocking Flow
6.4 Registers Associated with the Internal Flash Memory
Flash Control Register 2 (FCNT2)
<Address: H’0080 01E3>
9
1011121314
b15
b8
FPROT
0
<After reset: H’00>
b
Bit Name
Function
R
W
8–14
No function assigned. Fix to "0".
00
15
FPROT
0: Protection by lock bit effective
R
W
Unlock bit
1: Protection by lock bit invalidated
Flash Control Register 2 (FCNT2) controls invalidation of the internal flash memory protection by a lock bit
(protection against programming/erase operation). Protection of the internal flash memory is invalidated by
setting the FPROT bit to "1", so that any blocks protected by a lock bit can now be programmed or erased.
To set the FPROT bit to "1", write "0" and then "1" to the FPROT bit in succession while the FENTRY bit = "1". To
clear the FPROT bit to "0", write "0" to the FPROT bit.
If one of the following operations is attempted, the FPROT bit is cleared to "0".
1) Writing "0" to the FPROT bit
2) Entering a low-level signal to the FP pin
3) Clearing the FENTRY bit to "0"
4) Entering a low-level signal to the RESET# pin
