HD64F2149 Datasheet, PDF (698/1035 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

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User program mode
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.
Host
Programming/
erase control program
New application
program
The chip
Boot program
Flash memory
SCI
RAM
Transfer program
,
Application program
(old version)
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.
Host
New application
program
The chip
Boot program
Flash memory
Transfer program
SCI
RAM
Application program
(old version)
Programming/
erase control program
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.
Host
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.
Host
New application
program
The chip
Boot program
Flash memory
SCI
RAM
Transfer program
,^{Flash memory}
Programming/
erase control program
The chip
Boot program
Flash memory
Transfer program
New application
SCI
RAM
Programming/
erase control program
erase
program
Program execution state
Figure 22.5 User Program Mode (Example)
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