Datasheet

Section 23 ROM (H8S/2148 F-ZTAT A-Mask Version, H8S/2147 F-ZTAT A-Mask Version, H8S/2144 F-ZTAT A-Mask Version)
Rev. 4.00 Sep 27, 2006 page 713 of 1130
REJ09B0327-0400
23.8 Flash Memory Protection
There are three kinds of flash memory program/erase protection: hardware protection, software
protection, and error protection.
23.8.1 Hardware Protection
Hardware protection refers to a state in which programming/erasing of flash memory is forcibly
disabled or aborted. Hardware protection is reset by settings in flash memory control registers 1
and 2 (FLMCR1, FLMCR2) and erase block registers 1 and 2 (EBR1, EBR2). (See table 23.8.)
Table 23.8 Hardware Protection
Functions
Item Description Program Erase
Reset/standby
protection
• In a reset (including a WDT overflow reset)
and in hardware standby mode, software
standby mode, subactive mode, subsleep
mode, and watch mode, FLMCR1, FLMCR2,
EBR1, and EBR2 are initialized, and the
program/erase-protected state is entered.
• In a reset via the RES pin, the reset state is
not entered unless the RES pin is held low
until oscillation stabilizes after powering on.
In the case of a reset during operation, hold
the RES pin low for the RES pulse width
specified in the AC Characteristics section.
Yes Yes
23.8.2 Software Protection
Software protection can be implemented by setting the SWE bit in FLMCR1 and erase block
registers 1 and 2 (EBR1, EBR2). When software protection is in effect, setting the P or E bit in
flash memory control register 1 (FLMCR1) does not cause a transition to program mode or erase
mode. (See table 23.9.)