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Table 25.2 Crystal Resonator Parameters
Frequency (MHz)
R
(max) (Ω)
S
C
(max) (pF)
0
25.1.2
External Clock Input Method
Figure 25.4 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 or watch mode. External clock input
conditions are shown in table 25.3. The frequency of the external clock should be the same as that
of the system clock (φ).
EXTAL
XTAL
EXTAL
XTAL
8
10
80
70
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 25.4 Example of External Clock Input
Section 25 Clock Pulse Generator
12
16
60
50
External clock input
Open
External clock input
Rev. 1.00 May 09, 2008 Page 803 of 954
20
25
40
30
REJ09B0462-0100
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