UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 114

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

74
Cautions 1. The oscillator should be as close as possible to the X1 and X2 pins.
Remark Use of crystal resonator and ceramic resonator
(a) Crystal/ceramic oscillation
(b) External clock
2. No other signal lines should pass through the area enclosed by the dotted line.
Generally speaking, the oscillation frequency of a crystal resonator is extremely stable. It is therefore ideal for
performing high-precision time management (in clocks, frequency meters, etc.).
A ceramic resonator is inferior to a crystal resonator in terms of oscillation frequency stability, but it has three
advantages: a fast oscillation start-up time, small size, and low price. It is therefore suitable for general use (when
high-precision time management is not required). In addition, there are products with an internal capacitor, etc.,
which enable the number of parts and mounting area to be reduced.
PD74HC04, etc.
EXTC bit of .OSTS = 1
X1
X2
Figure 4-2 Clock Oscillator External Circuitry
PD784026
CHAPTER 4 CLOCK GENERATOR
V
X1
X2
SS
PD784026
EXTC bit of .OSTS = 0
Open
X1
X2
PD784026