Datasheet

Section 22 ROM (H8S/2138 F-ZTAT A-Mask Version, H8S/2134 F-ZTAT A-Mask Version)
Rev. 4.00 Jun 06, 2006 page 630 of 1004
REJ09B0301-0400
• User program mode
Flash memory
The chip
RAM
Host
Programming/
erase control program
SCI
Boot program
New application
program
Flash memory
The chip
RAM
Host
SCI
New application
program
Flash memory
The chip
RAM
Host
SCI
Flash memory
erase
Boot program
New application
program
Flash memory
The chip
Program execution state
RAM
Host
SCI
Boot program
Boot program
Application program
(old version)
New application
program
1. Initial state
(1) the program that will transfer the
programming/ erase control program to on-chip
RAM should be written into the flash memory by
the user beforehand. (2) The programming/erase
control program should be prepared in the host
or in the flash memory.
2. Programming/erase control program transfer
The transfer program in the flash memory is
executed, and the programming/erase control
program is transferred to RAM.
3. Flash memory initialization
The programming/erase program in RAM is
executed, and the flash memory is initialized (to
H'FF). Erasing can be performed in block units,
but not in byte units.
4. Writing new application program
Next, the new application program in the host is
written into the erased flash memory blocks. Do
not write to unerased blocks.
Programming/
erase control program
Programming/
erase control program
Programming/
erase control program
Transfer program
Application program
(old version)
Transfer program
Transfer program
Transfer program
Figure 22.5 User Program Mode (Example)