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2.17 Oscillation circuit
The M37221M6-XXXSP/FP has a internal oscillation circuits used to obtain the clocks required for operation.
Ordinarily, the frequency on clock input pin X
A quartz-crystal oscillator or ceramic resonator can be connected externally to these circuits.
(1) Oscillation circuit using a quartz-crystal oscillator or ceramic resonator
Figure 2.17.1 shows the circuit example using a quartz-crystal oscillator or a ceramic resonator. As
shown in the diagram, oscillation circuit can be constructed by connecting a ceramic resonator (a
quartz-crystal oscillator) between pins X
C
to the values recommended by the resonator manufacturer.
OUT
(2) External clock oscillation circuit
Supplying an external clock is possible, Figure 2.17.2 shows the circuit example.
M37221M6-XXXSP/FP
C
Fig. 2.17.1 Clock oscillation circuit using a ceramic
resonator
The M37221M6-XXXSP/FP has a CRT display clock
oscillation circuit, so that display clock can be obtained
simply by connecting a inductor and capacitor between
pins OSC1 and OSC2. Figure 2.17.3 shows the circuit
example.
Refer to "2.11.9 Clock for display."
X
X
IN
OUT
20
19
C
IN
OUT
7220 Group User's Manual
FUNCTIONAL DESCRIPTION
divided by 2 is the internal clock (internal timing output) φ .
IN
and X
. In this case, set the circuit constants for C
IN
OUT
Note:
In the stop mode, keep the X
signal at an "H" level.
Fig. 2.17.2 External clock input circuit example
Fig. 2.17.3 Clock oscillation circuit for CRT display
2.17 Oscillation circuit
M37221M6-XXXSP/FP
X
X
IN
OUT
19
20
Open
External oscillation circuit
V
CC
V
SS
M37221M6-XXXSP/FP
OSC1
OSC2
23
24
L
C2
C1
and
IN
pin input
IN
2-101
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