HD64F2638F20J Datasheet, PDF (820/1512 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2600 Series

Section 21A ROM
(H8S/2636 Group)
H8S/2639, H8S/2638, H8S/2636,
H8S/2630, H8S/2635 Group
To select user program mode, select a mode that enables the on-chip flash memory (mode 6 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 6 and 7.
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. If the program is to be located in external memory, the instruction for
writing to flash memory, and the following instruction, should be placed in on-chip RAM.
Figure 21A-10 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) 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*
Execute program/erase control
program (flash memory rewriting)
Clear FWE
Branch to flash memory application
program
Notes: 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 precautions on applying and disconnecting FWE, see section 21A.15, Flash
Memory Programming and Erasing Precautions.
Figure 21A-10 User Program Mode Execution Procedure
Page 770 of 1458
REJ09B0103-0800 Rev. 8.00
May 28, 2010