HD6432345 Datasheet, PDF (586/907 Pages) Hitachi Semiconductor – H8S/2345 F-ZTAT Hardware Manual

The flash memory itself cannot be read while the SWE bit is set to 1 to perform programming or
erasing, so the control program that performs programming and erasing should be run in on-chip
RAM or external memory.
Figure 17.19 shows the procedure for executing the program/erase control program when
transferred to on-chip RAM.
Write the FWE assessment program
and transfer program (and the program/
erase control program if necessary) to
flash memory beforehand
MD₂, MD₁, MD₀ = 110, 111
Reset-start
Transfer program/erase control
program to RAM
Branch to program/erase control
program in RAM area
FWE = high*
(Enter user program mode)
Execute program/erase control
program (flash memory rewriting)
Clear FWE*
(Clear user program mode)
Branch to flash memory application
program
Note: Do not apply a constant high level to the FWE pin. Apply a high level to the FWE pin
only when the flash memory is programmed or erased. Also, while a high level is
applied to the FWE pin, the watchdog timer should be activated to prevent
overprogramming or overerasing due to program runaway, etc.
* For further information on FWE application and disconnection, see section 17.14,
Flash Memory Programming and Erasing Precautions.
Figure 17.19 User Program Mode Execution Procedure
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