M16C28 Datasheet, PDF (327/423 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/Tiny SERIES

M16C/28 Group (M16C/28, M16C/28B)
18. Flash Memory Version
18.5.2 Flash Memory Control Register 1 (FMR1)
•FMR11 Bit
EW mode 1 is entered by setting the FMR11 bit to 1 (EW mode 1). The FMR11 bit is valid only when
the FMR01 bit is set to 1.
•FMR16 Bit
The combined setting of bits FMR02 and FMR16 enables program and erase in the user ROM area.
To set the FMR16 bit to 1, first set it to 0 and then 1. The FMR16 bit is valid only when the FMR01 bit
is set to 1 (CPU rewrite mode enable).
•FMR17 Bit
If the FMR17 bit is set to 1 (with wait state), 1 wait state is inserted when blocks A and B are accessed,
regardless of the content of the PM17 bit in the PM1 register. The PM17 bit setting is reflected to
access other blocks and internal RAM, regardless of the FMR17 bit setting.
Set the FMR17 bit to 1 (with wait state) to rewrite more than 100 times (U7, U9).
Table 18.4 Protection using FMR16 and FMR02
FMR16
FMR02 Block A, Block B Block 0, Block 1
0
0
write enabled
write disabled
0
1
write enabled
write disabled
1
0
write enabled
write disabled
1
1
write enabled
write enabled
other user block
write disabled
write disabled
write enabled
write enabled
18.5.3 Flash Memory Control Register 4 (FMR4)
•FMR40 Bit
The erase-suspend function is enabled when the FMR40 bit is set to 1 (enabled).
•FMR41 Bit
When the FMR41 bit is set to 1 by program during auto-erasing in EW mode 0, erase-suspend mode
is entered. In EW mode 1, the FMR41 bit is automatically set to 1 (suspend request) to enter erase-
suspend mode when an enabled interrupt request is generated. Set the FMR41 bit to 0 (erase restart)
to restart an auto-erasing operation.
•FMR46 Bit
The FMR46 bit is set to 0 during auto-erasing. It is set to 1 in erase-suspend mode.
Do not access to flash memory when the FMR46 bit is set to 0.
Rev. 2.00 Jan. 31, 2007 ^{page 307} of 385
REJ09B0047-0200