Figure 19.3 Boot Mode - Hitachi H8S/2215 Series Hardware Manual

Hitachi single-chip microcomputer
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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
This LSI
Boot program
Flash memory
Application program
(old version)
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
New application
program
This LSI
Boot program
Flash memory
Flash memory
preprogramming
erase
SCI or USB
RAM
SCI or USB
RAM
Boot program area
Programming control
program

Figure 19.3 Boot Mode

2. Programming control program transfer
When boot mode is entered, the boot program in
this LSI (originally incorporated in the chip) is
started and the programming control program in
the host is transferred to RAM via SCI or USB
communication. The boot program required for
flash memory erasing is automatically transferred
to the RAM boot program area.
Host
New application
program
This LSI
Boot program
Flash memory
Boot program area
Application program
(old version)
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
This LSI
Boot program
Flash memory
Boot program area
New application
program
Rev. 3.0, 10/02, page 561 of 686
SCI or USB
RAM
Programming control
program
SCI or USB
RAM
Programming control
program
Program execution state

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