M37544G Mitsubishi Electric, M37544G Datasheet - Page 33

• Manufacturer Part Number: M37544G
• Description: Single-Chip 8-Bit CMOS Microcomputer
• Manufacturer: Mitsubishi Electric

Clock Generating Circuit
An oscillation circuit can be formed by connecting a resonator be-
tween X
by connecting a resistor and a capacitor.
Use the circuit constants in accordance with the resonator
manufacturer's recommended values.
(1) Ring oscillator operation
When the MCU operates by the ring oscillator for the main clock,
connect X
The clock frequency of the ring oscillator depends on the supply
voltage and the operation temperature range.
Be careful that variable frequencies when designing application
products.
(2) Ceramic resonator and quartz-crystal oscillator
When the ceramic resonator and quartz-crystal oscillator is used
for the main clock, connect the ceramic / quartz-crystal oscillator
and the external circuit to pins X
tance. A feedback resistor is built in between pins X
(3) RC oscillation
When the RC oscillation is used for the main clock, connect the
X
the shortest distance and leave X
The frequency is affected by a capacitor, a resistor and a micro-
computer.
So, set the constants within the range of the frequency limits.
(4) External clock
When the external signal clock is used for the main clock, connect
the X
IN
pin to the external circuit of resistor R and the capacitor C at
IN
pin to the clock source and leave X
IN
IN
and X
pin to V
OUT
CC
, and an RC oscillation circuit can be formed
and leave X
IN
OUT
OUT
and X
pin open.
pin open.
OUT
OUT
at the shortest dis-
pin open.
IN
and X
OUT
.
Fig.38 Processing of X
eration
Fig. 40 External circuit of RC oscillatio
Fig. 39 External circuit of ceramic resonator and quartz-crys-
tal oscillator
Fig. 41 External clock input circuit
X
X
IN
X
IN
IN
C
External oscillation
circuit
IN
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
M37544
M37544
X
V
M37544
V
IN
CC
SS
MITSUBISHI MICROCOMPUTERS
IN
X
X
M37544
Open
and X
X
OUT
OUT
OUT
Rd
Note:
C
OUT
OUT
Note:
The clock frequency of the
ring oscillator depends on
the supply voltage and the
o p e r a t i o n t e m p e r a t u r e
range.
Be careful that variable fre-
quencies and obtain the
sufficient margin.
Note:
pins at ring oscillator op-
R
C
Externally connect a
damping resistor Rd
depending on the oscil-
lation frequency.
(A feedback resistor is
built-in.)
Use the resonator
manufacturer’s recom-
mended value because
constants such as ca-
pacitance depend on
the resonator.
7544 Group
Connect the external
circuit of resistor R
and the capacitor C at
the shortest distance.
The frequency is af-
fected by a capacitor,
a resistor and a micro-
computer.
So, set the constants
within the range of the
frequency limits.
Open
X
OUT
33