Not allowed
Signal A
Signal B
CL2
XTAL
EXTAL
CL1
Figure 6.10 Notes on Board Design around External Crystal
Input of External Clock Signal
Circuit Configuration: An external clock signal can be input as shown in the examples in figure
6.11. In example (b) in figure 6.11, the external clock signal should be kept high during standby.
If the XTAL pin is left open, make sure the stray capacitance does not exceed 10 pF.
EXTAL
XTAL
External clock input
Open
(a) Connections with XTAL pin left open
EXTAL
External clock input
74HC04
XTAL
(b) Connections with inverted clock input at XTAL pin
Figure 6.11 External Clock Input (Example)
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RENESAS [ RENESAS TECHNOLOGY CORP ]
