m30833fjgp Renesas Electronics Corporation., m30833fjgp Datasheet - Page 97

• Manufacturer Part Number: m30833fjgp
• Description: Renesas 16/32-bit Single-chip Microcomputer M16c Family / M32c/80 Series
• Manufacturer: Renesas Electronics Corporation.

R
R
M
e
E
3
. v
J
2
Figure 8.9 Main Clock Circuit Connection
0
8.1.1 Main Clock
1
C
9
3 .
B
8 /
Main clock oscillation circuit generates the main clock. The main clock becomes a clock source for the
CPU clock and peripheral function clock.
The main clock oscillation circuit is configured by connecting an oscillator or resonator between the X
and X
oscillation circuit in stop mode to reduce power consumption. The externally generated clock can be input
to the X
connection. Circuit constants vary with each oscillator. Use the circuit constant recommended by each
oscillator manufacturer.
The main clock divided-by-eight becomes the CPU clock after reset.
To reduce power consumption, set the CM05 bit in the CM0 register to "1" (main clock stopped) after
switching the CPU clock source to the sub clock or on-chip oscillator clock. In this case, X
"H". X
clock is input to the X
clock operation externally if necessary.
All clocks, including the main clock, stop in stop mode. Refer to 8.5 Power Consumption Control for details.
0
1
3
0
3
J
G
4
a
0 -
o r
n
OUT
IN
(Built-in Feedback Resistor)
3 .
1
u
IN
3
, 1
p
is pulled up by X
1
pins. The circuit has a built-in feedback resistor. The feedback resistor is separated from the
pin in the main clock oscillation circuit. Figure 8.9 shows an example of a main clock circuit
(
2
M
0
Microcomputer
NOTE:
0
3
6
2
1. Place a damping resistor if required. Resistance values vary depending on the oscillator setting.
C
8 /
Use values recommended by each oscillator manufacturer.
Place a feedback resistor between X
placing the resistor externally.
Page 74
X
, 3
V
OUT
X
IN
SS
IN
M
pin, the main clock does not stop even if the CM05 bit is set to "1". Terminate main
3
2
OUT
C
Oscillator
f o
Rd
8 /
4
via the feedback resistor which remains on. When an externally generated
3
(1)
8
) T
8
C
C
OUT
IN
IN
and X
(Built-in Feedback Resistor)
OUT
Microcomputer
if the oscillator manufacturer recommends
X
OUT
X
IN
Open
V
V
CC
SS
External Clock
8. Clock Generation Circuit
OUT
becomes
IN