HD6432633 Datasheet, PDF (1016/1453 Pages) Renesas Technology Corp – Series of Microcomputers (MCUs: microcomputer units)

Bits 1 and 0—Frequency Multiplication Factor (STC1, STC0): The STC bits specify the
frequency multiplication factor of the PLL circuit.
Bit 1
STC1
0
1
Bit 0
STC0
0
1
0
1
Description
×1
×2
×4
Setting prohibited
(Initial value)
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_d according to table 23A-2. An AT-cut parallel-resonance
crystal should be used.
C_L1
EXTAL
XTAL
R_d
C_L2
C_L1 = C_L2 = 10 to 22pF
Figure 23A-2 Connection of Crystal Resonator (Example)
Table 23A-2 Damping Resistance Value
Frequency (MHz) 2
4
8
12
16
20
25
R_d (Ω)
1k
500
200
0
0
0
0
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.
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