Hitachi H8S/2378, H8S/2378R Series Hardware Manual page 813

1. Initial state
(1) 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. (2) The programming/erase
control program should be prepared in the host
or in the flash memory.
Host
Programming/
erase control program
New application
program
This LSI
Boot program
Flash memory
Transfer program
Application program
(old version)
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.
Host
New application
program
This LSI
Boot program
Flash memory
Transfer program
Flash memory
erase
SCI
RAM
SCI
RAM
Programming/
erase control program
Figure 20.4 User Program Mode
2. Programming/erase control program transfer
When user program mode is entered, user
software confirms this fact, executes the transfer
program in the flash memory, and transfers the
programming/erase control program to RAM.
Host
New application
program
This LSI
Boot program
Flash memory
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.
Host
This LSI
Boot program
Flash memory
Transfer program
New application
program
Rev. 1.0, 09/01, page 769 of 904
SCI
RAM
Programming/
erase control program
SCI
RAM
Programming/
erase control program
Program execution state