M16C6S_09 Datasheet, PDF (190/208 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

M16C/6S Group
Usage Notes
Power Control
When entering wait mode, insert a JMP.B instruction before a WAIT instruction. Do not excute any instruc-
tions which can generate a write to RAM between the JMP.B and WAIT instructions. Disable the DMA
transfers, if a DMA transfer may occur between the JMP.B and WAIT instructions. After the WAIT instruc-
tion, insert at least 4 NOP instructions. When entering wait mode, the instruction queue reads ahead the
instructions following WAIT, and depending on timing, some of these may execute before the MCU enters
wait mode.
Program example when entering wait mode
Program Example: JMP.B
L1:
FSET
WAIT
NOP
NOP
NOP
NOP
L1 ; Insert JMP.B instruction before WAIT instruction
I;
; Enter wait mode
; More than 4 NOP instructions
When entering stop mode, insert a JMP.B instruction immediately after executing an instruction which
sets the CM10 bit in the CM1 register to 1, and then insert at least 4 NOP instructions. When entering stop
mode, the instruction queue reads ahead the instructions following the instruction which sets the CM10
bit to 1 (all clock stops), and, some of these may execute before the MCU enters stop mode or before the
interrupt routine for returning from stop mode.
Program example when entering stop mode
Program Example: FSET
BSET
JMP.B
L2:
NOP
NOP
NOP
NOP
I
CM10
L2
; Enter stop mode
; Insert JMP.B instruction
; More than 4 NOP instructions
Stop mode and wait mode is cancelled by a hardware reset or an interrupt. if an interrupt is to be used to
cancel stop mode and wait mode that interrupt must first have been enabled, and the priority level of the
interrupt which is not used to cancel must have been changed to 0.
Rev.5.01 Dec 10, 2009 page 190 of 201
REJ03B0014-0501