HD6417144 RENESAS [Renesas Technology Corp], HD6417144 Datasheet - Page 717

• Manufacturer Part Number: HD6417144
• Description: 32-Bit RISC Microcomputer SuperHTM RISC engine Family/SH7144 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

19.6.2
On-board programming/erasing of an individual flash memory block can also be performed in user
program mode by branching to a user program/erase control program. The user must set branching
conditions and provide on-board means of supplying programming data. The flash memory must
contain the user program/erase control program or a program that provides the user program/erase
control program from external memory. As the flash memory itself cannot be read during
programming/erasing, transfer the user program/erase control program to on-chip RAM or
external memory, and execute it. Figure 19.6 shows a sample procedure for programming/erasing
in user program mode. Prepare a user program/erase control program in accordance with the
description in section 19.8, Flash Memory Programming/Erasing.
Note: * Do not constantly apply a low level to the FWP pin. Only apply a low level to the FWP pin when
Figure 19.6 Programming/Erasing Flowchart Example in User Program Mode
Programming/Erasing in User Program Mode
programming or erasing the flash memory. To prevent excessive programming or excessive erasing,
while a low level is being applied to the FWP pin, activate the watchdog timer in case of handling CPU
runaways.
Execute user program/erase control
program (flash memory rewrite)
Branch to user program/erase
Transfer user program/erase
control program to RAM
control program in RAM
Branch to flash memory
application program
Program/erase?
FWP = low*
FWP = high
Reset-start
Yes
No
Rev.4.00 Mar. 27, 2008 Page 673 of 882
Branch to flash memory
application program
19. Flash Memory (F-ZTAT Version)
REJ09B0108-0400