D12320VF25V Datasheet, PDF (773/1146 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 17 ROM
17.25.2 Software Protection
Software protection is set up in any of three ways: by disabling the downloading of on-chip
programs for programming and erasing, by means of a key code, and by the RAM-emulation
register.
Table 17.55 Software Protection
Function to Be Protected
Item
Description
Download Program/Erase
Protection by the
SCO bit
• Clearing the SCO bit in the FCCS
register makes the device enter a
program/erase-protected state, and
this disables the downloading of the
programming/erasing programs.
Protection by the
FKEY register
• Downloading and
programming/erasing are disabled
unless the required key code is
written in the FKEY register. Different
key codes are used for downloading
and for programming/erasing.
Emulation protection •
Setting the RAMS bit in the RAM
emulation register (RAMER) makes
the device enter a program/erase-
protected state.
17.25.3 Error Protection
Error protection is a mechanism for aborting programming or erasure when an error occurs, in the
form of the microcomputer entering runaway during programming/erasing of the flash memory or
operations that are not according to the established procedures for programming/erasing. Aborting
programming or erasure in such cases prevents damage to the flash memory due to excessive
programming or erasing.
If the microcomputer malfunctions during programming/erasing of the flash memory, the FLER
bit in the FCCS register is set to 1 and the device enters the error-protection state, and this aborts
the programming or erasure.
The FLER bit is set in the following conditions:
Rev.7.00 Feb. 14, 2007 page 739 of 1108
REJ09B0089-0700