Oscillator; 3.1 Connecting A Crystal Resonator - Renesas H8S/2633 Series Hardware Manual

Bits 1 and 0—Frequency Multiplication Factor (STC1, STC0): The STC bits specify the
frequency multiplication factor of the PLL circuit.
Bit 1 Bit 0
STC1 STC0
0 0
1
1 0
1
Note: A system clock frequency multiplied by the multiplication factor (STC1 and STC0) should
not exceed the maximum operating frequency defined in section 25 Electrical
Characteristics.
23A.3 Oscillator
Clock pulses can be supplied by connecting a crystal resonator, or by input of an external clock.
23A.3.1 Connecting a Crystal Resonator
Circuit Configuration: A crystal resonator can be connected as shown in the example in figure
23A-2. Select the damping resistance R
crystal should be used.
Figure 23A-2 Connection of Crystal Resonator (Example)
Table 23A-2 Damping Resistance Value
Frequency (MHz) 2
R (Ω) 1 k
d
Crystal Resonator: Figure 23A-3 shows the equivalent circuit of the crystal resonator. Use a
crystal resonator that has the characteristics shown in table 23A-3.
962
Description
×1
×2
×4
Setting prohibited
according to table 23A-2. An AT-cut parallel-resonance
d
EXTAL
XTAL
R
d
4 8
500 200
C
L1
C C = C
L2 L1
12 16
0 0
(Initial value)
= 10 to 22pF
L2
20 25
0 0