On-Board Programming Modes - Hitachi H8/3062 Hardware Manual

18.4.2

On-Board Programming Modes

Example of Boot Mode Operation
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.
Programming control
New application
H8/3064F-ZTAT B-mask version
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.
New application
H8/3064F-ZTAT B-mask version
Boot program
Flash memory
Flash memory
prewrite-erase
Host
program
program
SCI
RAM
Host
program
SCI
RAM
Boot program area
Programming control
program
2. Programming control program transfer
When boot mode is entered, the boot program
in the H8/3064F-ZTAT B-mask version
(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
H8/3064F-ZTAT B-mask version
Boot program
Flash memory
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
H8/3064F-ZTAT B-mask version
Boot program
Flash memory
New application
program
SCI
RAM
Boot program area
Programming control
program
SCI
RAM
Boot program area
Programming control
program
Program execution state
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