Functional Description - Epson S1F76640 Technical Manual

5. FUNCTIONAL DESCRIPTION

! CR oscillation circuit
The S1F76640 is equipped with a CR oscillation circuit as an internal oscillation circuit, connecting external
resistor R for oscillation between the OSC1 and OSC2 pins (Fig.5.1).
OSC
OSC1
OSC2
Fig.5.1 CR oscillation circuit
Note 1: The oscillation frequency varies depending on the wiring capacity, so the wire between the OSC1 and
OSC2 pins and R
To set the external resistor R
efficiency in Figures 7.12 and 7.13, and then obtain R
The relationship between R
<2MΩ.
400kΩ<R
OSC
1
=
・
R A
OSC
f
OSC
Therefore, the R value can be obtained from the relational expression above.
OSC
(Recommended oscillation frequency: 10kHz to 30kHz (R
For external clock operation, open the OSC2 pin as shown in Fig.5.2 and input external clocks (duty 50%) from
the OSC1 pin.
S1F76640 Technical Manual (Rev.1.5)
(Note 1)
R
OSC
must be short as much as possible.
OSC
, first obtain the oscillation frequency f
OSC
and f can be briefly expressed by the following equation on condition that
OSC OSC
(where A is a constant: GND = 0V, V
5. FUNCTIONAL DESCRIPTION
OSC1
OSC2 Open
Fig.5.2 External Clock Operation
corresponding to the f
OSC
= 5V, f
DD
: 2MΩ to 680kΩ)
OSC
EPSON
External clock
that satisfies the maximum
OSC
in Fig.7.1.
OSC
A = 2.0 × 10
10
(Ω•Hz))
OSC
5