Flash Memory Protection; Hardware Protection; Software Protection - Hitachi H8S/2338 Series Hardware Manual

17.8

Flash Memory Protection

There are three kinds of flash memory program/erase protection: hardware protection, software
protection, and error protection.
17.8.1

Hardware Protection

Hardware protection refers to a state in which programming/erasing of flash memory is forcibly
disabled or aborted. Settings in flash memory control registers 1 and 2 (FLMCR1, FLMCR2) and
erase block registers 1 and 2 (EBR1, EBR2) are reset. (See table 17-10.)
Table 17-10 Hardware Protection
Item
FWE pin protection
Reset/standby
protection
17.8.2

Software Protection

Software protection can be implemented by setting the SWE bit in flash memory control register 1
(FLMCR1), erase block registers 1 and 2 (EBR1, EBR2), and the RAMS bit in the RAM
emulation register (RAMER). When software protection is in effect, setting the P or E bit in
FLMCR1 does not cause a transition to program mode or erase mode. (See table 17-11.)
Description
•
When a low level is input to the FWE pin,
FLMCR1, FLMCR2, EBR1, and EBR2 are
initialized, and the program/erase-
protected state is entered.
•
In a reset (including a WDT overflow reset)
and in standby 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.
Functions
Program Erase
Yes Yes
Yes Yes
573