Datasheet

Section 20 Flash Memory (0.18-μm F-ZTAT Version)
Rev.6.00 Mar. 18, 2009 Page 779 of 980
REJ09B0050-0600
20.5.2 Software Protection
Software protection is set up by disabling the downloading of on-chip programs for programming
and erasing or by means of a key code register.
Table 20.10 Software Protection
Function to be Protected
Item Description Download
Program/
Erase
Protection by the
SCO bit
• The program/erase-protected state
is entered by clearing the SCO bit in
FCCS which disables the down-
loading of the programming/erasing
programs.
Protection by the
FKEY register
• Downloading and
programming/erasing are disabled
unless the required key code is
written in FKEY. Different key codes
are used for downloading and for
programming/erasing.
20.5.3 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 error-protection state is entered, and this aborts the
programming or erasure.