H8SLASH3028F datasheet(627/923 Pages) RENESAS

627 / 923 page

Rev. 2.00, 09/03, page 597 of 890

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.

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