Boot Mode - Hitachi F-ZTAT H8/3039 Series Hardware Manual

On-Board Programming Modes

• Boot mode

1. Initial state
The flash memory is in the erased state when the
device is shipped. The description here applies to
the case where the old program version or data
is being rewritten. The user should prepare the
programming control program and new
application program beforehand in the host.
Programming control
New application
This chip
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, entire flash
memory erasure is performed, without regard to
blocks.
Programming control
New application
This chip
Boot program
Flash memory
Flash memory
erase
450
Host
program
program
SCI
RAM
Host
program
program
SCI
RAM
Boot program area
Figure 15-3 Boot Mode
2. Programming control program transfer
When boot mode is entered, the boot program in
this chip (originally 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
Programming control
program
New application
program
This chip
Boot program
Flash memory
Application program
(old version)
4. Writing new application program
The programming control program transferred
from the host to RAM by SCI communication is
executed, and the new application program in the
host is written into the flash memory.
Host
This chip
Boot program
Flash memory
New application
program
SCI
RAM
Boot program area
SCI
RAM
Programming
control program
Program execution state