External Clock Input - Hitachi H8S/2378, H8S/2378R Series Hardware Manual

21.2.2

External Clock Input

An external clock signal can be input as shown in the examples in figure 21.4. If the XTAL pin is
left open, make sure that parasitic capacitance is no more than 10 pF. When the counter clock is
input to the XTAL pin, make sure that the external clock is held high in standby mode.
Table 21.3 shows the input conditions for the external clock
EXTAL
XTAL
EXTAL
XTAL
(a) XTAL pin left open
(b) Counter clock input at XTAL pin
Figure 21.4 External Clock Input (Examples)
External clock input
Open
External clock input
Rev. 1.0, 09/01, page 797 of 904