upd78f0730 Renesas Electronics Corporation., upd78f0730 Datasheet - Page 94

• Manufacturer Part Number: upd78f0730
• Description: 8-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

5.4 System Clock Oscillator
5.4.1 X1 oscillator
pins.
94
The X1 oscillator oscillates with a crystal resonator or ceramic resonator (1 to 20 MHz) connected to the X1 and X2
Figure 5-11 shows an example of the external circuit of the X1 oscillator.
Cautions 1. When using the X1 oscillator, wire as follows in the area enclosed by the broken lines in the
Figure 5-12 shows examples of incorrect resonator connection.
Figure 5-11. Example of External Circuit of X1 Oscillator (Crystal or Ceramic Oscillation)
Figure 5-11 to avoid an adverse effect from wiring capacitance.
• 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
• Always make the ground point of the oscillator capacitor the same potential as V
• Do not fetch signals from the oscillator.
(a) Too long wiring
line through which a high fluctuating current flows.
not ground the capacitor to a ground pattern through which a high current flows.
V
Figure 5-12. Examples of Incorrect Resonator Connection (1/2)
SS
X1
Preliminary User’s Manual U19014EJ1V0UD
CHAPTER 5 CLOCK GENERATOR
X2
Crystal resonator
or
ceramic resonator
V
X1
X2
SS
V
SS
(b) Crossed signal line
X1
PORT
X2
SS
. Do