HD6432621 Hitachi, HD6432621 Datasheet - Page 681

• Manufacturer Part Number: HD6432621
• Description: (HD64F262x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

Figure 19-9 shows the procedure for executing the program/erase control program when
transferred to on-chip RAM.
Notes: 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 section19.13,
Flash Memory Programming and Erasing Precautions.
Figure 19-9 User Program Mode Execution Procedure
Write the FWE assessment program and
transfer program (and the program/erase
control program if necessary) beforehand
Branch to flash memory application
program (flash memory rewriting)
Branch to program/erase control
Transfer program/erase control
Execute program/erase control
MD2, MD1, MD0 = 110, 111
program in RAM area
program to RAM
FWE = high*
Clear FWE*
Reset-start
program
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