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M16C/62P Group (M16C/62P, M16C/62PT)
10.4.3 Stop Mode
In stop mode, all oscillator circuits are turned off, so are the CPU clock and the peripheral function clocks.
Therefore, the CPU and the peripheral functions clocked by these clocks stop operating. The least
amount of power is consumed in this mode. If the voltage applied to VCC1 and VCC2 pins is VRAM or
more, the internal RAM is retained. When applying 2.7 or less voltage to VCC1 and VCC2 pins, make
sure VCC1 ≥ VCC2 ≥ VRAM.
However, the peripheral functions clocked by external signals keep operating. The following interrupts
can be used to exit stop mode.
______
• NMI interrupt
• Key interrupt
______
• INT interrupt
• Timer A, Timer B interrupt (when counting external pulses in event counter mode)
• Serial I/O interrupt (when external clock is selected)
• Voltage down detection interrupt (Refer to 6.1 Voltage Down Detection Interrupt for an Oper-
ating Condition)
10.4.3.1 Entering Stop Mode
The microcomputer is placed into stop mode by setting the CM10 bit in the CM1 register to "1" (all
clocks turned off). At the same time, the CM06 bit in the CM0 register is set to "1" (divide-by-8 mode)
and the CM15 bit in the CM1 register is set to "1" (main clock oscillator circuit drive capability high).
Before entering stop mode, set the CM20 bit in the CM2 register to "0" (oscillation stop, re-oscillation
detection function disable).
Also, if the CM11 bit in the CM1 register is "1" (PLL clock for the CPU clock source), set the CM11 bit
to "0" (main clock for the CPU clock source) and the PLC07 bit in the PLC0 register to "0" (PLL turned
off) before entering stop mode.
10.4.3.2 Pin Status in Stop Mode
Table 10.6 lists pin status during stop mode.
R
e
. v
2
3 .
0
S
e
p
0
, 1
2
0
0
4
R
E
J
0
9
B
0
1
8
5
0 -
2
3
0
Z
page 80
f o
3
6
4
10. Clock Generating Circuit
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