M16C28 Datasheet, PDF (326/423 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 Register Description
Figure 18.7 shows the flash memory control register 0 and flash memory control register 1. Figure 18.8
shows the flash memory control register 4.
18.5.1 Flash Memory Control Register 0 (FMR0)
•FMR 00 Bit
The FMR00 bit indicates the operating state of the flash memory. Its value is 0 while the program,
erase, or erase-suspend command is being executed, otherwise, it is 1.
•FMR01 Bit
The MICROCOMPUTER can accept commands when the FMR01 bit is set to 1 (CPU rewrite mode).
To set the FMR01 bit to 1, first set it to 0 and then 1. The FMR01 bit is set to 0 only by writing 0.
•FMR02 Bit
The combined setting of bits FMR02 and FMR16 enables program and erase in the user ROM area.
See Table 18.4 for setting details. To set the FMR02 bit to 1, first set it to 0 and then 1. The FMR02
bit is valid only when the FMR01 bit is set to 1 (CPU rewrite mode enable).
•FMSTP Bit
The FMSTP bit initializes the flash memory control circuits and minimizes power consumption in the
flash memory. Access to the on-chip flash memory is disabled when the FMSTP bit is set to 1. Set the
FMSTP bit by program in a space other than the flash memory.
Set the FMSTP bit to 1 if one of the following occurs:
•A flash memory access error occurs during erasing or programming in EW mode 0 (FMR00 bit does
not switch back to 1 (ready)).
•Low-power consumption mode or on-chip oscillator low-power consumption mode is entered.
Figure 18.11 shows a flow chart illustrating how to start and stop the flash memory before and after
entering low power mode. Follow the procedure in this flow chart.
When entering stop or wait mode while the CPU rewrite mode is disabled, do not set the FMR0
register because the on-chip flash memory is automatically turned off and turned back on when
exiting.
•FMR06 Bit
The FMR06 bit is a read-only bit indicating an auto-program operation state. The FMR06 bit is set to
1 when a program error occurs; otherwise, it is set to 0. For details, refer to 18.8.4 Full Status Check.
•FMR07 Bit
The FMR07 bit is a read-only bit indicating an auto-erase operation status. The FMR07 bit is set to 1
when an erase error occurs; otherwise, it is set to 0. For details, refer to 18.8.4 Full Status Check.
Figure 18.9 shows a EW mode 0 set/reset flowchart, Figure 18.10 shows a EW mode 1 set/reset flow-
chart.
Rev. 2.00 Jan. 31, 2007 ^{page 306} of 385
REJ09B0047-0200