H8S2639 Datasheet, PDF (954/1547 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2600 Series

Section 21C ROM (H8S/2635 Group)
21C.9.1 Program Mode
When writing data or programs to flash memory, the program/program-verify flowchart shown in
figure 21C-12 should be followed. Performing programming operations according to this
flowchart will enable data or programs to be written to flash memory without subjecting the
device to voltage stress or sacrificing program data reliability. Programming should be carried out
128 bytes at a time.
The wait times after bits are set or cleared in the flash memory control register 1 (FLMCR1) and
the maximum number of programming operations (N) are shown in table 24-22 in section 24.2.7,
and in table 24-34 in section 24.3.7, and in table 24-46 in section 24.4.7, Flash Memory
Characteristics.
Following the elapse of (t_sswe) µs or more after the SWE bit is set to 1 in FLMCR1, 128-byte data
is written consecutively to the write addresses. The lower 8 bits of the first address written to must
be H'00 and H'80, 128 consecutive byte data transfers are performed. The program address and
program data are latched in the flash memory. A 128-byte data transfer must be performed even if
writing fewer than 128 bytes; in this case, H'FF data must be written to the extra addresses.
Next, the watchdog timer (WDT) is set to prevent overprogramming due to program runaway, etc.
Set a value greater than (t_spsu + t_sp + t_cp + t_cpsu) µs as the WDT overflow period. Preparation for
entering program mode (program setup) is performed next by setting the PSU bit in FLMCR1.
The operating mode is then switched to program mode by setting the P bit in FLMCR1 after the
elapse of at least (t_spsu) µs. The time during which the P bit is set is the flash memory programming
time. Make a program setting so that the time for one programming operation is within the range
of (t_sp) µs.
The wait time after P bit setting must be changed according to the degree of progress through the
programming operation. For details see “Notes on Program/Program-Verify Procedure.”
Rev. 6.00 Feb 22, 2005 page 894 of 1484
REJ09B0103-0600