r4f2456 Renesas Electronics Corporation., r4f2456 Datasheet - Page 1188

• Manufacturer Part Number: r4f2456
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

Section 24 Clock Pulse Generator
24.2
Clock pulses can be supplied by connecting a crystal resonator, or by input of an external clock.
24.2.1
A crystal resonator can be connected as shown in the example in figure 24.2. Select the damping
resistance R
crystal resonator is used, the range of its frequencies is from 8 to 20 MHz.
Figure 24.3 shows the equivalent circuit of the crystal resonator. Use a crystal resonator that has
the characteristics shown in table 24.2.
Table 24.1 Damping Resistance Value
Rev. 1.00 Sep. 19, 2008 Page 1158 of 1342
REJ09B0467-0100
Frequency (MHz)
R
d
(Ω)
Oscillator
Connecting a Crystal Resonator
d
according to table 24.1. An AT-cut parallel-resonance type should be used. When a
Figure 24.2 Connection of Crystal Resonator (Example)
XTAL
EXTAL
XTAL
Figure 24.3 Crystal Resonator Equivalent Circuit
8
200
R
d
L
C
C
C
C
L
0
L1
L2
12
0
AT-cut parallel-resonance type
R
s
C
L1
= C
EXTAL
16
0
L2
= 10 to 22 pF
20
0