Renesas H8S/2318 series, Hardware Manual

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Rev. 5.00, 12/03page 774 of 1088
18.3.2 External Clock Input
Circuit Configuration: An external clock signal can be input as shown in the examples in figure
18-5. If the XTAL pin is left open, make sure that stray capacitance is no more than 10 pF.
In example (b), make sure that the external clock is held high in standby mode.
EXTAL
XTAL
External clock input
Open
(a) XTAL pin left open
EXTAL
XTAL
External clock input
(b) Complementary clock input at XTAL pin
Figure 18-5 External Clock Input (Examples)
External Clock: The external clock signal should have the same frequency as the system clock
(
φ
).
Table 18-4 and figure 18-6 show the input conditions for the external clock.