External Clock Input Method; Figure 19.4 Example Of External Clock Input - Renesas H8S/2111B Hardware Manual

19.1.2

External Clock Input Method

Figure 19.4 shows a typical method of connecting an external clock signal. To leave the XTAL pin
open, incidental capacitance should be 10 pF or less.
To input an inverted clock to the XTAL pin, the external clock should be set to high in standby
mode, subactive mode, subsleep mode, and watch mode. External clock input conditions are
shown in table 19.3. The frequency of the external clock should be the same as that of the system
clock (φ).
(b) Example of external clock input when an inverted clock is input to XTAL pin
EXTAL
XTAL
(a) Example of external clock input when XTAL pin left open
EXTAL
XTAL

Figure 19.4 Example of External Clock Input

External clock input
Open
External clock input
Rev. 1.00, 05/04, page 457 of 544