SH7047 Datasheet, PDF (92/764 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTMRISC engine Family/SH7000 Series

4.1 Oscillator
Clock pulses can be supplied from a connected crystal resonator or an external clock.
4.1.1 Connecting a Crystal Resonator
Circuit Configuration: A crystal resonator can be connected as shown in figure 4.2. Use the
damping resistance (Rd) listed in table 4.1. Use an AT-cut parallel-resonance type crystal
resonator that has a resonance frequency of 4 to 12.5 MHz. It is recommended to consult crystal
dealer concerning the compatibility of the crystal resonator and the LSI.
C_L1
EXTAL
XTAL
R_d
C_L2
C_L1 = C_L2 = 18–22 pF (Recommended value)
Figure 4.2 Connection of the Crystal Resonator (Example)
Table 4.1 Damping Resistance Values
Frequency (MHz)
4
8
10
12.5
Rd (Ω)
500
200
0
0
Crystal Resonator: Figure 4.3 shows an equivalent circuit of the crystal resonator. Use a crystal
resonator with the characteristics listed in table 4.2.
XTAL
C_L
L
Rs
EXTAL
C₀
AT-cut parallel-resonance type
Figure 4.3 Crystal Resonator Equivalent Circuit
Table 4.2 Crystal Resonator Characteristics
Frequency (MHz)
4
8
10
12.5
Rs max (Ω)
120
80
60
50
C0 max (pF)
7
7
7
7
Rev. 2.00, 09/04, page 52 of 720