M16C65 Datasheet, PDF (787/829 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M16C/60

Under development
M16C/65 Group
Preliminary Specification
This is a preliminary specification and is subject to change.
31. Precautions
31.7.3 Stop Mode
• When exiting stop mode by hardware reset, drive the RESET pin low until main clock oscillation is
stabilized.
• Set the MR0 bit in the TAiMR register (i = 0 to 4) to 0 (pulse not output) when using timer A to exit
stop mode.
• When entering stop mode, insert a JMP.B instruction immediately after executing an instruction
that sets the CM10 bit in the CM1 register to 1, and then insert at least four NOP instructions.
When entering stop mode, the instruction queue reads ahead the instructions following the instruc-
tion which sets the CM10 bit to 1 (all clock stop). Thus, some of the instructions may be executed
before the MCU enters stop mode or before the interrupt routine for returning from stop mode.
Program example when entering stop mode
Program Example:
L2:
FSET
BSET
JMP.B
NOP
NOP
NOP
NOP
I
0, CM1 ; Enter stop mode
L2
; Insert a JMP.B instruction
; At least four NOP instructions
• The CLKOUT pin outputs a high-level signal in stop mode. Thus, if stop mode is entered right after
output on the CLKOUT pin changes state from high to low, the high-level durations of the output
signal to the CLKOUT pin becomes shorter.
Stop mode
CLKOUT pin output
• When the FMR23 bit in the FMR2 register is 1 (low current consumption read mode enabled), do
not enter stop mode. To enter stop mode, execute an instruction to set the CM10 bit in the CM1
register to 1 (stop mode) after setting the FMR23 bit to 0 (low current consumption read mode dis-
abled), setting the FMR01 bit to 0 (CPU rewrite mode disabled), and disabling DMA transfer.
31.7.4 Low Current Consumption Read Mode
• Enter low current consumption read mode through slow read mode (refer to Figure 9.4 “Setting and
Canceling of Low Current Consumption Read Mode”).
• When the FMR23 bit in the FMR2 register is 1 (low current consumption read mode enabled), do
not set the FMSTP bit to 1 (flash memory stopped). Also, when the FMSTP bit is 1, do not set the
FMR23 bit to 1.
REJ09B0484-0030 Rev.0.30 Sep 09, 2008
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