p2125vps20 Renesas Electronics Corporation., p2125vps20 Datasheet - Page 510

• Manufacturer Part Number: p2125vps20
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 19 Flash Memory (0.18-µm F-ZTAT Version)
• Flash Key Code Register (FKEY)
Rev. 1.00 Sep. 21, 2006 Page 472 of 658
REJ09B0310-0100
Bit
7
6
5
4
3
2
1
0
FKEY is for software protection that enables download of an on-chip program and
programming/erasing of flash memory. Before setting the SCO bit to 1 to download an on-chip
program or before executing the downloaded programming/erasing program, the key code
must be written, otherwise the processing cannot be executed.
Bit Name
K7
K6
K5
K4
K3
K2
K1
K0
Initial
Value
0
0
0
0
0
0
0
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Description
Key Code
Only when H'A5 is written, writing to the SCO bit is valid.
When a value other than H'A5 is written to FKEY, 1
cannot be set to the SCO bit. Therefore downloading to
the on-chip RAM cannot be executed. Only when H'5A is
written, programming/erasing can be executed. Even if
the on-chip programming/erasing program is executed,
the flash memory cannot be programmed or erased when
a value other than H'5A is written to FKEY.
H'A5: Writing to the SCO bit is enabled. (The SCO bit
H'5A: Programming/erasing is enabled. (Software
H'00: Initial value
cannot be set by a value other than H'A5.)
protection state is entered for a value other than
H'5A.)