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7.4.2
User Program Mode
When set to user program mode, the chip can program and erase its flash memory by executing a
user program/erase control program. Therefore, on-board reprogramming of the on-chip flash
memory can be carried out by providing on-board means of FWE control and supply of
programming data, and storing a program/erase control program in part of the program area as
necessary.
In this mode, the chip starts up in mode 1 and applies a high level to the FWE pin.
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 7.11 shows the procedure for executing the program/erase control program when
transferred to on-chip RAM.
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.
Figure 7.11 User Program Mode Execution Procedure (Preliminary)
Rev. 1.0, 02/00, page 146 of 1141
Write the FWE assessment program and
transfer program (and the program/erase
control program if necessary) beforehand
MD0 = 1
Reset start
Transfer program/erase
control program to RAM
Branch to program/erase control
program in RAM area
FWE = high
Execute program/erase control
program (flash memory rewriting)
Clear FWE
Branch to flash memory
application program
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