upd78f0103hmca1-5a4-a Renesas Electronics Corporation., upd78f0103hmca1-5a4-a Datasheet - Page 92

• Manufacturer Part Number: upd78f0103hmca1-5a4-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

(2) External RC oscillator
92
Caution When using the external RC oscillator, wire as follows in the area enclosed by the broken lines
Figure 5-11 shows an example of incorrect connections for RC oscillation.
The external RC oscillator is oscillated by the resistor (R) and capacitor (C) connected across the CL1 and CL2
pins.
An external clock can also be input to the circuit. In this case, input the clock signal to the CL1 pin, and input the
inverted signal to the CL2 pin.
Figure 5-10 shows the external circuit of the external RC oscillator.
• Keep the wiring length as short as possible.
• Do not cross the wiring with the other signal lines. Do not route the wiring near a signal line
• Always make the ground point of the oscillator capacitor the same potential as V
• Do not fetch signals from the oscillator.
in Figure 5-10 to avoid an adverse effect from wiring capacitance.
through which a high fluctuating current flows.
ground the capacitor to a ground pattern through which a high current flows.
(a) RC oscillation
C
R
Figure 5-10. External Circuit of External RC Oscillator
V
CL1
CL2
SS
CHAPTER 5 CLOCK GENERATOR
User’s Manual U16846EJ3V0UD
External
clock
(b) External clock
CL1
CL2
SS
. Do not