UPD784224 Datasheet, PDF (32/92 Pages) NEC – 16/8-BIT SINGLE-CHIP MICROCONTROLLERS

µPD784224, 784225, 784224Y, 784225Y
Figure 7-3. Example of Using Main System Clock Oscillator
(1) Crystal/ceramic oscillation
(2) External clock
X2
VSS1
X1
VSS
Crystal resorator
or
ceramic resonator
X2
External
X1
clock
µ PD74HCU04
Figure 7-4. Example of Using Subsystem Clock Oscillator
(1) Crystal oscillation
(2) External clock
VSS1
VSS
XT2
32.768
kHz
XT1
XT2
External
clock
XT1
µPD74HCU04
Caution When using the main system clock and subsystem clock oscillator, wire the dotted portions in
Figures 7-3 and 7-4 as follows to avoid adverse influence from wiring capacitance.
• Keep the wiring length as short as possible.
• Do not cross the wiring with other signal lines.
• Do not route the wiring in the vicinity of lines through which a high alternating current flows.
• Always keep the potential at the ground point of the capacitor in the oscillator the same as
VSS1. Do not ground to a ground pattern through which a high current flows.
• Do not extract signals from the oscillator.
Note that the subsystem clock oscillator has a low amplification factor to reduce the current
consumption.
32
Data Sheet U12376EJ1V0DS00