HD64F3028F25 Datasheet, PDF (629/925 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

3. See section 4.2.2, Reset Sequence, and section 18.11, Flash Memory Programming and
Erasing Precautions. The H8/3028F-ZTAT requires a minimum of 20 system clock
cycles for a reset during operation.
18.5.2 User Program Mode
When set to user program mode, the H8/3028F-ZTAT can program and erase its flash memory by
executing a user program/erase control program. Therefore, on-board reprogramming of the on-
chip flash memory can be carried out by providing on-board means of FWE control and supply of
programming data, and storing a program/erase control program in part of the program area as
necessary.
To select user program mode, select a mode that enables the on-chip ROM (mode 5 or 7), and
apply a high level to the FWE pin. In this mode, on-chip supporting modules other than flash
memory operate as they normally would in modes 5 and 7.
Flash memory programming/erasing should not be carried out in mode 6. When mode 6 is set, the
FWE pin must be driven low.
The flash memory itself cannot be read while being programmed or erased, so the program that
performs programming should be placed in external memory or transferred to RAM and executed
there.
Figure 18.8 shows the execution procedure when user program mode is entered during program
execution in RAM. It is also possible to start from user program mode in a reset-start.
Rev. 2.00, 09/03, page 597 of 890