Renesas M16C/6NK Technical Information Seite 95

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Rev.2.10 Apr 14, 2006 page 71 of 378
REJ09B0124-0210
M16C/6N Group (M16C/6NK, M16C/6NM) 8. Clock Generation Circuit
8.4.2 Wait Mode
In wait mode, the CPU clock is turned off, so are the CPU (because operated by the CPU clock) and the
watchdog timer. However, if the PM22 bit in the PM2 register is 1 (on-chip oscillator clock for the watchdog
timer count source), the watchdog timer remains active. Because the main clock, sub clock and on-chip
oscillator clock all are on, the peripheral functions using these clocks keep operating.
8.4.2.1 Peripheral Function Clock Stop Function
If the CM02 bit in the CM0 register is 1 (peripheral function clocks turned off during wait mode), the f1, f2,
f8, f32, f1SIO, f8SIO, f32SIO, fAD, fCAN0, and fCAN1 clocks are turned off when in wait mode, with the
power consumption reduced that much. However, fC32 remains on.
8.4.2.2 Entering Wait Mode
The MCU is placed into wait mode by executing the WAIT instruction.
When the CM11 bit = 1 (CPU clock source is the PLL clock), be sure to set the CM11 bit in the CM1
register to 0 (CPU clock source is the main clock) before going to wait mode. The power consumption of
the chip can be reduced by setting the PLC07 bit in the PLC0 register to 0 (PLL stops).
8.4.2.3 Pin Status During Wait Mode
Table 8.4 lists the Pin Status During Wait Mode.
Table 8.4 Pin Status During Wait Mode
NOTES:
1. Not available memory expansion and microprocessor modes in T/V-ver..
2. Not available the bus control pins in T/V-ver..
8.4.2.4 Exiting Wait Mode
______
The MCU exits wait mode by a hardware reset, NMI interrupt or peripheral function interrupt.
______
If the MCU exits wait mode by a hardware reset or NMI interrupt, set the peripheral function interrupt
priority bits ILVL2 to ILVL0 to 000b (interrupt disabled) before executing the WAIT instruction.
The peripheral function interrupts are affected by the CM02 bit. If the CM02 bit is 0 (peripheral function
clocks not turned off during wait mode), peripheral function interrupts can be used to exit wait mode. If
the CM02 bit is 1 (peripheral function clocks turned off during wait mode), the peripheral functions using
the peripheral function clocks stop operating, so that only the peripheral functions clocked by external
signals can be used to exit wait mode.
Table 8.5 lists the Interrupts to Exit Wait Mode and Use Conditions.
Pin
Memory Expansion Mode
Single-chip Mode
Microprocessor Mode
(1)
A0 to A19, D0 to D15, Retains status before wait mode Does not become a bus control pin
_______ _______ ________
CS0 to CS3, BHE
(2)
______ _______ _________ _________
RD, WR, WRL, WRH
(2)
H
___________
HLDA, BCLK
(2)
H
ALE
(2)
L
I/O ports Retains status before wait mode Retains status before wait mode
CLKOUT Does not become a CLKOUT pin Does not stop
CM02 bit = 0: Does not stop
CM02 bit = 1: Retains status before
wait mode
When fC selected
When f8, f32
selected
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