Datasheet

Section 22 Flash Memory
Rev. 3.00 Sep. 28, 2009 Page 688 of 910
REJ09B0350-0300
(4) Flash Key Code Register (FKEY)
FKEY is a register for software protection that enables to download the on-chip program and
perform programming/erasing of the flash memory.
Bit Bit Name
Initial
Value
R/W Description
7
6
5
4
3
2
1
0
K7
K6
K5
K4
K3
K2
K1
K0
0
0
0
0
0
0
0
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Key Code
When H'A5 is written to FKEY, writing to the SCO bit in
FCCS is enabled. When a value other than H'A5 is
written, the SCO bit cannot be set to 1. Therefore, the
on-chip program cannot be downloaded to the on-chip
RAM.
Only when H'5A is written can programming/erasing of
the flash memory be executed. When a value other than
H'5A is written, even if the programming/erasing
program is executed, programming/erasing cannot be
performed.
H'A5: Writing to the SCO bit is enabled. (The SCO bit
cannot be set to 1 when FKEY is a value other
than H'A5.)
H'5A: Programming/erasing of the flash memory is
enabled. (When FKEY is a value other than H'A5,
the software protection state is entered.)
H'00: Initial value