HD6412340 HITACHI [Hitachi Semiconductor], HD6412340 Datasheet - Page 586

• Manufacturer Part Number: HD6412340
• Description: H8S/2345 F-ZTAT Hardware Manual
• Manufacturer: HITACHI [Hitachi Semiconductor]

The flash memory itself cannot be read while the SWE bit is set to 1 to perform programming or
erasing, so the control program that performs programming and erasing should be run in on-chip
RAM or external memory.
Figure 17.19 shows the procedure for executing the program/erase control program when
transferred to on-chip RAM.
574
Note: Do not apply a constant high level to the FWE pin. Apply a high level to the FWE pin
only when the flash memory is programmed or erased. Also, while a high level is
applied to the FWE pin, the watchdog timer should be activated to prevent
overprogramming or overerasing due to program runaway, etc.
* For further information on FWE application and disconnection, see section 17.14,
Flash Memory Programming and Erasing Precautions.
Figure 17.19 User Program Mode Execution Procedure
Write the FWE assessment program
and transfer program (and the program/
erase control program if necessary) to
flash memory beforehand
Branch to flash memory application
program (flash memory rewriting)
Branch to program/erase control
Transfer program/erase control
Execute program/erase control
(Enter user program mode)
(Clear user program mode)
MD
program in RAM area
2
, MD
program to RAM
FWE = high*
Clear FWE*
Reset-start
1
program
, MD
0
= 110, 111