Epson S1C33L03 User Manual

In the low-speed (OSC1) oscillation circuit, either a crystal oscillation or an external clock input can be selected as

the type of oscillation circuit.

Figure 6.2 shows the structure of the low-speed (OSC1) oscillation circuit.

V

SS

OSC2

OSC1

R

f

C

D1

C

G1

Oscillation circuit 
control signal

Oscillation circuit 
control signal

X'tal1

f

OSC1

OSC2

OSC1

External
clock

N.C.

V

SS

V

DD

f

OSC1

(1) Crystal oscillation circuit

V

SS

OSC2

OSC1

Oscillation circuit 
control signal

Low level

(3) When not used

(2) External clock input

Figure 6.2  Low-Speed (OSC1) Oscillation Circuit

When using a crystal oscillation for this circuit, connect a crystal resonator X'tal1 (32.768 kHz, Typ.) and feedback

resistor (Rf) between the OSC1 and OSC2 pins, and two capacitors (C

G1

, C

D1

) between the OSC1 pin and V

SS

 and

the OSC2 pin and V

SS

, respectively.

When an external clock source is used, leave the OSC2 pin open and input a square-wave clock to the OSC1 pin.

If the low-speed (OSC1) oscillation circuit is not used, connect the OSC1 pin to V

SS 

and leave the OSC2 pin open.

The oscillation frequency is 32.768 kHz (Typ.). Use a crystal resonator or external clock that oscillates at this

frequency. No other frequency can be used for clock applications.

For details on oscillation characteristics and the external clock input characteristics, refer to "Electrical

Characteristics".