HD6432345 Datasheet, PDF (566/907 Pages) Hitachi Semiconductor – H8S/2345 F-ZTAT Hardware Manual

!On-Board Programming Modes
• Boot mode
1. Initial state
The old program version or data remains written
in the flash memory. The user should prepare the
programming control program and new
application program beforehand in the host.
Host
Programming control
program
New application
program
H8S/2345 F-ZTAT chip
Boot program
Flash memory
SCI
RAM
Application program
(old version)
2. Programming control program transfer
When boot mode is entered, the boot program in
the H8S/2345 chip (originally incorporated in the
chip) is started and the programming control
program in the host is transferred to RAM via SCI
communication. The boot program required for
flash memory erasing is automatically transferred
to the RAM boot program area.
Host
New application
program
H8S/2345 F-ZTAT chip
Boot program
Flash memory
SCI
RAM
Application program
(old version)
Boot program area
Programming control
program
3. Flash memory initialization
The erase program in the boot program area (in
RAM) is executed, and the flash memory is
initialized (to H'FF). In boot mode, entire flash
memory erasure is performed, without regard to
blocks.
Host
New application
program
H8S/2345 F-ZTAT chip
Boot program
Flash memory
SCI
RAM
Flash memory
erase
Boot program area
Programming control
program
4. Writing new application program
The programming control program transferred
from the host to RAM is executed, and the new
application program in the host is written into the
flash memory.
Host
H8S/2345 F-ZTAT chip
Boot program
Flash memory
New application
program
SCI
RAM
Boot program area
Programming control
program
Program execution state
Figure 17.9 Boot Mode
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