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Rev. 1.00, 05/04, page 434 of 544
<Flash memory>
<This LSI>
<RAM>
<Host>
Programming
control program
SCI
Application
program
(old version)
Boot program
New
application program
<Flash memory>
<This LSI>
<RAM>
<Host>
SCI
Application
program
(old version)
Boot program area
New
application program
<Flash memory>
<This LSI>
<RAM>
<Host>
SCI
Flash memory
erase
Boot program
New
application program
<Flash memory>
<This LSI>
Program execution state
<RAM>
<Host>
SCI
New
application
program
Boot program
Programming
control program
Boot program area
Boot program
1. Initial state
The flash memory is erased at shipment.
The following describes how to write over
an old-version application program or data in
the flash memory. The user should prepare
the programming control program and
new application program beforehand in the host.
2. SCI communication check
When boot mode is entered, the boot program in
this LSI (originally incorporated in the chip) is started
and SCI communication is checked. Then the boot
program required for flash memory erasing is
automatically transferred to the RAM 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.
4. Writing new application program
The programming control program transferred from
the host to RAM via SCI communication is executed,
and the new application program in the host is written
into the flash memory.
Boot program area
Programming
control program
Programming
control program
Figure 18.3 Boot Mode