M16C6S_09 Datasheet, PDF (37/208 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

M16C/6S Group
Clock Generation Circuit
Table 1.7.2. Setting Clock Related Bit and Modes
Modes
High-speed mode
Medium-
speed
mode
divided by 2
divided by 4
divided by 8
divided by 16
On-chip
oscillator
mode
divided by 1
divided by 2
divided by 4
divided by 8
divided by 16
CM2 register
CM21
0
0
0
0
0
1
1
1
1
1
CM1 register
CM17, CM16
002
012
102
112
002
012
102
112
CM0 register
CM06
0
0
0
1
0
0
0
0
1
0
Note: The divide-by-n value can be selected the same way as in On-chip Oscillator mode.
(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 of PM2 register is “1” (On-chip Oscillator clock for the watchdog
timer count source), the watchdog timer remains active. Because the main clock, and On-chip Oscillator
clock are on, the peripheral functions using these clocks keep operating.
• Peripheral Function Clock Stop Function
If the CM02 bit is “1” (peripheral function clocks turned off during wait mode), the f1, f2, f8, f32, f1SIO,
f8SIO, and f32SIO clocks are turned off when in wait mode, with the power consumption reduced that
much.
• Entering Wait Mode
The microcomputer is placed into wait mode by executing the WAIT instruction.
• Pin Status During Wait Mode
Table 1.7.3 lists pin status during wait mode
• Exiting Wait Mode
The microcomputer is moved out of wait mode by a hardware reset or peripheral function interrupt.
If the microcomputer is to be moved out of exit wait mode by a hardware reset, set the peripheral
function interrupt priority ILVL2 to ILVL0 bits to “0002” (interrupts disabled) before executing the WAIT
instruction.
The peripheral function interrupts are affected by the CM02 bit. If CM02 bit is “0” (peripheral function
clocks not turned off during wait mode), all peripheral function interrupts can be used to exit wait
mode. If CM02 bit is “1” (peripheral function clocks turned off during wait mode), the peripheral func-
tions 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 1.7.4 lists the interrupts to exit wait mode.
Rev.5.01 Dec 10, 2009 page 37 of 201
REJ03B0014-0501