H8S2268_09 Datasheet, PDF (577/712 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2200 Series

Section 20 ROM
20.8.1 Program/Program-Verify
When writing data or programs to the flash memory, the program/program-verify flowchart shown
in figure 20.10 should be followed. Performing programming operations according to this
flowchart will enable data or programs to be written to the flash memory without subjecting the
chip to voltage stress or sacrificing program data reliability.
1. Programming must be done to an empty address. Do not reprogram an address to which
programming has already been performed.
2. Programming should be carried out 128 bytes at a time. 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.
3. Prepare the following data storage areas in RAM: A 128-byte programming data area, a 128-
byte reprogramming data area, and a 128-byte additional-programming data area. Perform
reprogramming data computation and additional programming data computation according to
figure 20.10.
4. Consecutively transfer 128 bytes of data in byte units from the reprogramming data area or
additional-programming data area to the flash memory. The program address and 128-byte
data are latched in the flash memory. The lower 8 bits of the start address in the flash memory
destination area must be H'00 or H'80.
5. The time during which the P1 bit is set to 1 is the programming time. Figure 20.10 shows the
allowable programming times.
6. The watchdog timer (WDT) is set to prevent overprogramming due to program runaway, etc.
Set a value greater than (tspsu + tsp200 + tcp + tcpsu) µs as the WDT overflow period.
7. For a dummy write to a verify address, write 1-byte data H'FF to an address whose lower 1 bit
is B'0. Verify data can be read in words from the address to which a dummy write was
performed.
8. The maximum number of repetitions of the program/program-verify sequence of the same bit
is (N).
Rev. 5.00 Sep. 01, 2009 Page 525 of 656
REJ09B0071-0500