UPD784044 Datasheet, PDF (31/90 Pages) NEC – 16-BIT SINGLE-CHIP MICROCONTROLLER

µPD784044(A), 784046(A)
Figure 7-3. Example of Using Oscillation Circuit
(1) Crystal/ceramic oscillation
µ PD784046(A)
VSS
X1
X2
(2) External clock input
(a) EXTC bit of OSTS = 1
µPD784046(A)
X1
µPD74HC04, etc.
(b) EXTC bit of OSTS = 0
µPD784046(A)
X1
X2
Leave unconnected X2
Caution When using the clock oscillation circuit, wire the portion enclosed by the dotted line in the above
figure as follows to avoid adverse effects of 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 ground point of the capacitor of the oscillation circuit at the same potential
as VSS. Do not ground the capacitor to a ground pattern through which a high current flows.
• Do not extract signals from the oscillation circuit.
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