M16C30P_07 Datasheet, PDF (71/317 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/30 SERIES

M16C/30P Group
9. Clock Generating Circuit
9.4.3 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 9.5 Interrupts to Exit Stop Mode and Use Conditions
Interrupt
CM02=1
NMI Interrupt
Can be used
Key Input Interrupt
Can be used
INT Interrupt
Can be used
Timer A Interrupt
Timer B Interrupt
Can be used when counting external pulses in event counter mode
Serial Interface Interrupt
Can be used when operating with external clock
9.4.3.1 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).
9.4.3.2 Pin Status in Stop Mode
Table 9.6 lists Pin Status in Stop Mode.
Table 9.6 Pin Status in Stop Mode
Pin
Memory Expansion Mode
Microprocessor Mode
Single-Chip Mode
A0 to A19, D0 to D15, CS0 to CS3, ^{Retains status before stop mode Does not become a bus control}
BHE
pin
RD, WR, WRL, WRH
“H”
HLDA, BCLK
“H”
ALE
Indeterminate
I/O ports
Retains status before stop mode Retains status before stop mode
CLKOUT When fC selected
Does not become a CLKOUT pin “H”
When f8, f32 selected
Retains status before stop mode
Rev.1.22 Mar 29, 2007 Page 55 of 291
REJ09B0179-0122