Datasheet

Section 20 Flash Memory (0.35-μm F-ZTAT Version)
Rev.7.00 Mar. 18, 2009 page 836 of 1136
REJ09B0109-0700
Flash memory
This LSI
RAM
Host
Programming control
program
SCI
Application program
(old version)
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
prewrite-erase
Boot program
New application
program
Flash memory
This LSI
Program execution state
RAM
Host
SCI
New application
program
Boot program
Programming control
program
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.
2. Programming control program transfer
When boot
mode is entered, the boot program in
the chip (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 eras
ing 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, entire flash
memory erasure is performed, without regard to
blocks.
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 wri
tten into the
flash memory.
Programming control
program
Boot programBoot program
Boot program area Boot program area
Programming control
program
Figure 20.3 Boot Mode