HD64F7144F50V Datasheet, PDF (101/932 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

4. Clock Pulse Generator
4.1 Oscillator
Clock pulses can be supplied from a connected crystal resonator or an external clock.
4.1.1 Connecting Crystal Resonator
A crystal resonator can be connected as shown in figure 4.2. Use the damping resistance (Rd)
listed in table 4.2. Use an crystal resonator that has a resonance frequency of 4 to 12.5 MHz. It is
recommended to consult the crystal resonator manufacturer 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 Crystal Resonator (Example)
Table 4.2 Damping Resistance Values (Recommended Values)
Frequency (MHz)
4
8
10
12.5
Rd (Ω)
500
200
0
0
Figure 4.3 shows an equivalent circuit of the crystal resonator. Use a crystal resonator with the
characteristics listed in table 4.3.
XTAL
C_L
L
Rs
EXTAL
C₀
Figure 4.3 Crystal Resonator Equivalent Circuit
Rev.4.00 Mar. 27, 2008 Page 55 of 882
REJ09B0108-0400