h8s-2172 Renesas Electronics Corporation., h8s-2172 Datasheet - Page 419

• Manufacturer Part Number: h8s-2172
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family H8s-2100 Series
• Manufacturer: Renesas Electronics Corporation.

• Flash Key Code Register (FKEY)
FKEY is a register for software protection that enables download of on-chip program and
programming/erasing of flash memory. Before setting the SCO bit to 1 in order to download on-
chip program or executing the downloaded programming/erasing program, these processing
cannot be executed if the key code is not written.
Bit
7
6
5
4
3
2
1
0
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 the 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 the 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. (The value other
H'00: Initial value
cannot be set by the value other than H'A5.)
than H'A5 is in software protection state.)
Rev. 2.00, 03/04, page 387 of 534