Datasheet

Section 22 Flash Memory
Rev. 3.00 Sep. 28, 2009 Page 725 of 910
REJ09B0350-0300
22.9.2 Software Protection
The software protection protects the flash memory against programming/erasing by disabling
download of the programming/erasing program and using the key code.
Table 22.15 Software Protection
Function to be Protected
Item Description Download
Programming/
Erasing
Protection
by SCO bit
The programming/erasing protection state is
entered when the SCO bit in FCCS is cleared to 0
to disable download of the programming/erasing
programs.
O O
Protection
by FKEY
The programming/erasing protection state is
entered because download and
programming/erasing are disabled unless the
required key code is written in FKEY.
O O
22.9.3 Error Protection
Error protection is a mechanism for aborting programming or erasure when a CPU runaway
occurs or operations not according to the programming/erasing procedures are detected during
programming/erasing of the flash memory. Aborting programming or erasure in such cases
prevents damage to the flash memory due to excessive programming or erasing.
If an error occurs during programming/erasing of the flash memory, the FLER bit in FCCS is set
to 1 and the error protection state is entered.
• When an interrupt request, such as NMI, occurs during programming/erasing.
• When the flash memory is read from during programming/erasing (including a vector read or
an instruction fetch).
• When a SLEEP instruction is executed (including software-standby mode) during
programming/erasing.