Renesas H8S Series Hardware Manual page 606

• User program mode
1. Initial state
(1) The FWE assessment program that confirms
that the FWE pin has been driven high, and (2)
the program that will transfer the programming/
erase control program to on-chip RAM should be
written into the flash memory by the user
beforehand. (3) The programming/erase control
program should be prepared in the host or in the
flash memory.
H8S/2357 Group chip
Boot program
Flash memory
FWE assessment
Transfer program
Application program
3. Flash memory initialization
The programming/erase program in RAM is
executed, and the flash memory is initialized (to
H'FF). Erasing can be performed in block units,
but not in byte units.
H8S/2357 Group chip
Boot program
Flash memory
FWE assessment
Transfer program
Flash memory
Rev.6.00 Oct.28.2004 page 578 of 1016
REJ09B0138-0600H
Host
Programming/
erase control program
New application
program
RAM
program
(old version)
Host
New application
program
RAM
program
Programming/
erase control program
erase
Figure 19-10 User Program Mode (Example)
2. Programming/erase control program transfer
When the FWE pin is driven high, user software
confirms this fact, executes the transfer program
in the flash memory, and transfers the
programming/erase control program to RAM.
H8S/2357 Group chip
SCI
Boot program
Flash memory
FWE assessment
program
Transfer program
Application program
(old version)
4. Writing new application program
Next, the new application program in the host is
written into the erased flash memory blocks. Do
not write to unerased blocks.
H8S/2357 Group chip
SCI
Boot program
Flash memory
FWE assessment
program
Transfer program
New application
program
Host
New application
program
SCI
RAM
Programming/
erase control program
Host
SCI
RAM
Programming/
erase control program
Program execution state