HD64F3048VTF8 Datasheet, PDF (641/903 Pages) Renesas Technology Corp – Hardware Manual Renesas 8-Bit Single-Chip

Section 18 ROM (H8/3048F-ONE: Single Power Supply, H8/3048B Mask ROM Version)
Program mode
Erase mode
WDT reset, RES = 0 or STBY = 0
Reset or standby
(hardware protection)
RD VF PR ER FLER = 0
Error
occurrence
Error occurrence
(software standby)
RD VF PR ER INIT FLER = 0
WDT reset,
RES = 0 or
STBY = 0
WDT reset,
RES = 0 or
STBY = 0
FLMCR1, FLMCR2,
EBR initialization
state
Error protection mode
Software
standby mode
Error protection mode
(software standby)
RD VF PR ER FLER = 1
Software standby
mode release
RD VF PR ER INIT FLER = 1
FLMCR1, EBR
initialization state
Legend:
RD: Memory read possible
VF: Verify-read possible
PR: Programming possible
ER: Erasing possible
RD: Memory read not possible
VF: Verify-read not possible
PR: Programming not possible
ER: Erasing not possible
INIT: Register initialization state
Figure 18.15 Flash Memory State Transitions
(When High Level Is Applied to FWE Pin in Mode 5, 6, and 7 (On-Chip ROM Enabled))
The error protection function is invalid for abnormal operations other than the FLER bit setting
conditions. Also, if a certain time has elapsed before this protection state is entered, damage may
already have been caused to the flash memory. Consequently, this function cannot provide
complete protection against damage to flash memory.
To prevent such abnormal operations, therefore, it is necessary to ensure correct operation in
accordance with the program/erase algorithm, with the flash write enable (FWE) voltage applied,
and to conduct constant monitoring for MCU errors, internally and externally, using the watchdog
timer or other means. There may also be cases where the flash memory is in an erroneous
programming or erroneous erasing state at the point of transition to this protection mode, or where
programming or erasing is not properly carried out because of an abort. In cases such as these, a
forced recovery (program rewrite) must be executed using boot mode. However, it may also
happen that boot mode cannot be normally initiated because of overprogramming or overerasing.
Rev. 3.00 Sep 27, 2006 page 613 of 872
REJ09B0325-0300