
Rev.2.10 Apr 14, 2006 page 342 of 378
REJ09B0124-0210
M16C/6N Group (M16C/6NK, M16C/6NM) 23. Usage Notes
23.5 Power Control
•
____________
When exiting stop mode by hardware reset, set RESET pin to “L” until a main clock oscillation is stabilized.
• Set the MR0 bit in the TAiMR register (i = 0 to 4) to 0 (pulse is not output) to use the timer A to exit stop
mode.
• In the main clock oscillation or low power dissipation mode, set the CM02 bit in the CM0 register to 0 (do
not stop peripheral function clock in wait mode) before shifting to stop mode.
• When entering wait mode, insert a JMP.B instruction before a WAIT instruction. Do not execute any
instructions 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
instruction, insert at least 4 NOP instructions. When entering wait mode, the instruction queue roadstead
the instructions following WAIT, and depending on timing, some of these may execute before the
microcomputer enters wait mode.
Program example when entering wait mode
Program Example: JMP.B L1 ; Insert JMP.B instruction before WAIT instruction
L1:
FSET I ;
WAIT ; Enter wait mode
NOP ; More than 4 NOP instructions
NOP
NOP
NOP
• When entering stop mode, describe as follows.
(1) To use the BSET instruction for entering stop mode:
Write the BSET instruction (BSET bit, base:16) as described below.
When entering stop mode, DMA transfer must be disabled.
BSET 0,CM1 ; Stop mode setting [bit, base:16]
JMP.B L1 ;
L1:
NOP ; Countermeasure to avoid the program from
NOP ; stopping by reading instruction ahead
NOP ; (insert 4 or more NOPs)
NOP ;
(2) To use the MOV instruction for entering stop mode:
Write the MOV instruction (MOV.B #IMM8, abs16) as described below.
When entering stop mode, DMA transfer must be disabled.
Change the
src
value (marked as “#21”), depending on your usage condition.
MOV.B #21H,CM1 ; Stop mode setting [#IMM8, abs16]
JMP.B L1 ;
L1:
NOP ; Countermeasure to avoid the program from
NOP ; stopping by reading instruction ahead
NOP ; (insert 4 or more NOPs)
NOP ;
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