r4f2426 Renesas Electronics Corporation., r4f2426 Datasheet - Page 1124

• Manufacturer Part Number: r4f2426
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

Section 23 Clock Pulse Generator
Table 23.2 Crystal Resonator Characteristics
23.2.2
An external clock signal can be input as shown in the examples in figure 23.4. 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 23.3 shows the input conditions for the external clock. When an external clock is used, the
range of its frequencies is from 8 to 20 MHz.
Rev. 1.00 Sep. 19, 2008 Page 1096 of 1270
REJ09B0466-0100
Frequency (MHz)
R
C
S
0
max (pF)
max (Ω)
External Clock Input
Figure 23.4 Connection of External Clock Input (Examples)
EXTAL
EXTAL
XTAL
XTAL
8
80
7
(b) Counter clock input at XTAL pin
(a) XTAL pin left open
12
60
7
Open state
External clock input
External clock input
16
50
7
20
40
7