NEC PD78F9488 - Manual (Page 103)

CHAPTER 5 CLOCK GENERATOR
User’s Manual U15331EJ4V1UD
103
5.4.3 Example of incorrect resonator connection
Figure 5-9 shows examples of incorrect resonator connection.
Figure 5-9. Examples of Incorrect Resonator Connection (1/2)
(a) Too long wiring (b) Crossed signal line
V SS X1 X2 V SS X1 X2
PORTn
(n = 0 to 3, 5)
(c) Wiring near high fluctuating current (d) Current flowing through ground line of oscillator
(potential at points A, B, and C fluctuates)
V
SS
X1 X2
High current
V
SS
X1
A B C
P
mn
V DD
High current
X2
Remark When using the subsystem clock, read X1 and X2 as XT1 and XT2, respectively, and connect a resistor
to XT2 in series.