External Clock Input Method; Figure 23.4 Example Of External Clock Input; Table 23.2 Crystal Resonator Parameters - Renesas H8S Series Hardware Manual

Table 23.2 Crystal Resonator Parameters

Frequency (MHz)
R (max) (Ω)
S
C (max) (pF)
0
23.1.2

External Clock Input Method

Figure 23.4 shows a typical method of inputting 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 23.3. The frequency of the
external clock should be the same as that of the system clock (φ).
EXTAL
XTAL
EXTAL
XTAL
4 8
120 80
7 7
(a) Example of external clock input when XTAL pin is left open
(b) Example of external clock input when an inverted clock is input to XTAL pin

Figure 23.4 Example of External Clock Input

Section 23 Clock Pulse Generator
10 12
70 60
7 7
External clock input
Open
External clock input
Rev. 3.00 Jul. 14, 2005 Page 851 of 986
16 20
50 40
7 7
REJ09B0098-0300