HD64F3437TF16 Datasheet, PDF (534/752 Pages) Hitachi Semiconductor – 12 V must not be applied to the S-mask model (single-power-supply specification), as this may permanently damage the device.

;;;;On-Board Programming Modes
• Boot Mode
1. Initial state
The flash memory is in the erased state when
shipped. The procedure for rewriting an old
version of an application program or data is
described here. The user should prepare an
on-board update routine and the new
application program beforehand in the host.
Host
On-board update routine
New application
program
H8/3437SF
Boot program
Flash memory
SCI
RAM
Application
program
(old version)
2. SCI communication check
When boot mode is entered, the boot program
in the H8/3437SF (already incorporated in the
chip) is started, an SCI communication check is
carried out, and the boot program required for
flash memory erasing is automatically
transferred to the RAM boot program area.
Host
On-board update routine
New application
program
H8/3437SF
Boot program
Flash memory
SCI
RAM
Application
program
(old version)
Boot program area
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, total flash
memory erasure is performed, without regard to
blocks.
Host
On-board update routine
New application
program
H8/3437SF
Boot program
Flash memory
SCI
RAM
Flash memory
erase
Boot program area
4. Writing new application program
The on-board update routine in the host to
RAM is transferred to RAM by SCI
communication and executed, and the new
application program in the host is written into
the flash memory.
Host
H8/3437SF
Boot program
Flash memory
New application
program
SCI
RAM
On-board update
routine
: Program execution state
Figure 21.3 Boot Mode
505