Stop Mode - Renesas M16C/62P Series Hardware Manual

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. Table 10.6 lists Interrupts to Stop Mode and Use Conditions
Table 10.6 Interrupts to Stop Mode and Use Conditions
Interrupt
NMI Interrupt
Key Input Interrupt
INT Interrupt
Timer A Interrupt
Timer B Interrupt
Serial Interface Interrupt
Low Voltage Detection
Interrupt
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 10.7 lists Pin Status in Stop Mode.
Table 10.7 Pin Status in Stop Mode
Pin
A0 to A19, D0 to D15, CS0 to CS3,
BHE
RD, WR, WRL, WRH
HLDA, BCLK
ALE
I/O ports
CLKOUT When fC selected
When f8, f32 selected
Rev.2.41 Jan 10, 2006
REJ09B0185-0241
http://www.xinpian.net
Can be used
Can be used
Can be used
Can be used
(when counting external pulses in event counter mode)
Can be used
(when external clock is selected)
Can be used
(Refer to 6.1 Low Voltage Detection Interrupt for an Operating Condition)
Memory Expansion Mode
Microprocessor Mode
Retains status before stop mode Does not become a bus control
"H"
"H"
indeterminate
Retains status before stop mode Retains status before stop mode
Does not become a CLKOUT pin "H"
Page 98 of 390
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10. Clock Generation Circuit
Condition
Single-Chip Mode
pin
Retains status before stop mode
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