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M16C/29 Group
21.4.1 EW0 Mode
The microcomputer enters CPU rewrite mode by setting the FMR01 bit in the FMR0 register to "1" (CPU
rewrite mode enabled) and is ready to acknowledge the software commands. EW0 mode is selected by
setting the FMR11 bit in the FMR1 register to "0". When setting the FMR01 bit to "1", set to "1" after first
writing "0". The software commands control programming and erasing. The FMR0 register or the status
register indicates whether a programming or erasing operation is completed. When entering the erase-
suspend during the auto-erasing, set the FMR40 bit to "1" (erase-suspend enabled) and the FMR41 bit to
"1" (suspend request). And wait for td(SR-ES). After verifying the FMR46 bit is set to "1" (auto-erase
stop), access to the user ROM area. When setting the FMR41 bit to "0" (erase restart), auto-erasing is
restarted.
21.4.2 EW1 Mode
EW1 mode is selected by setting the FMR11 bit to "1" after the FMR01 bit is set to "1". (set to "1" after first
writing "0"). The FMR0 register indicates whether or not a programming or an erasing operation is com-
pleted. Do not execute the software commands of read status register in EW1 mode.
When an erase/program operation is initiated the CPU halts all program execution until the operation is
completed or erase-suspend is requeird. When enabling an erase suspend function, set the FMR40 bit to
"1" (erase suspend enabled) and execute block erase commands. Also, preliminarily set an interrupt to
enter the erase-suspend to an interrupt enabled status. After td(SR-ES) from an interrupt request and
entering erase suspend, an interrupt can be acknowledged. When an interrupt request is generated, the
FMR41 bit is automatically set to "1" (suspend request) and an auto-erasing is halted. If an auto-erasing
is not completed (the FMR00 bit is "0") after an interrupt process completed, set the FMR41 bit to "0" (to
restart the erase operation) and execute block erase commands again.
Rev.1.00 Nov 01,2004
REJ09B0101-0100Z
page 373 of 402
21. Flash Memory Version
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