HD64F2149 Datasheet, PDF (697/1035 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

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.
Host
Programming control
program
New application
program
The chip
Boot program
Flash memory
SCI
RAM
Application program
(old version)
2. Programming control program transfer
When boot mode is entered, the boot program in
the 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
The chip
Boot program
Flash memory
SCI
RAM
Application program
(old version)
Boot program area
Programming control
program
3. Flashmemoryinitialization
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.
Host
New application
program
The chip
 !"Bootprogram
Flash memory
SCI
RAM
Flash memory
erase
Boot program area
Programming control
program
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
The chip
Boot program
Flash memory
New application
program
SCI
RAM
Boot program
area
Programming
control program
 ^{Programexecutionstate}
Figure 22.4 Boot Mode
663