HD6413008F RENESAS [Renesas Technology Corp], HD6413008F Datasheet - Page 493

• Manufacturer Part Number: HD6413008F
• Description: Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series
• Manufacturer: RENESAS [Renesas Technology Corp]

17.2
Clock pulses can be supplied by connecting a crystal resonator, or by input of an external clock
signal.
17.2.1
Circuit Configuration: A crystal resonator can be connected as in the example in figure 17.2.
Damping resistance Rd should be selected according to table 17.1 (1), and external capacitances
C
If a crystal resonator with a frequency higher than 20 MHz is connected, the external load
capacitance values in table 17.1 (2) should not exceed 10 [pF]. Also, in order to improve the
accuracy of the oscillation frequency, a thorough study of oscillation matching evaluation, etc.,
should be carried out when deciding the circuit constants.
Table 17.1 (1)
Rd (Ω)
Note: A crystal resonator between 2 MHz and 25 MHz can be used. If the chip is to be operated
Damping
Resistance
Value
L1
and C
at less than 2 MHz, the on-chip frequency divider should be used. (A crystal resonator of
less than 2 MHz cannot be used.)
L2
Oscillator Circuit
Connecting a Crystal Resonator
according to table 17.1 (2). An AT-cut parallel-resonance crystal should be used.
2
1 k
Damping Resistance Value
2 < f ≤ 4 4 < f ≤8 8 < f ≤ 10 10 < f ≤ 13 13 < f ≤ 16 16 < f ≤ 18 18 < f ≤ 25
500
Figure 17.2 Connection of Crystal Resonator (Example)
200
EXTAL
XTAL
0
Rd
Frequency f (MHz)
0
Rev.4.00 Aug. 20, 2007 Page 449 of 638
C
C
L1
L2
0
17. Clock Pulse Generator
0
REJ09B0395-0400
0