HD6417706 RENESAS [Renesas Technology Corp], HD6417706 Datasheet - Page 390

• Manufacturer Part Number: HD6417706
• Description: Renesas 32-Bit RISC Microcomputer Super RISC engine Family/SH7700 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

13.4.5
Crystal oscillator circuit constants (recommended values) are shown in table 13.2, and the RTC
crystal oscillator circuit in figure 13.5.
Table 13.2 Recommended Oscillator Circuit Constants (Recommended Values)
Rev. 4.00, 03/04, page 344 of 660
f
32.768 kHz
osc
Notes:
Crystal Oscillator Circuit
1.
2.
3.
4.
5.
6.
SH7706
Select either the C in or C out side for frequency adjustment variable capacitor according to requirements
such as frequency range, degree of stability, etc.
Built-in resistance value R f (Typ value) = 10 M , R D (Typ value) = 400 k
C in and C out values include floating capacitance due to the wiring. Take care when using a ground
plane.
The crystal oscillation settling time depends on the mounted circuit constants, floating capacitance, etc.,
and should be decided after consultation with the crystal resonator manufacturer.
Place the crystal resonator and load capacitors C in and C out as close as possible to the chip.
(Correct oscillation may not be possible if there is externally induced noise in the EXTAL2 and XTAL2
pins.)
Ensure that the crystal resonator connection pin (EXTAL2, XTAL2) wiring is routed as far away as
possible from other power lines (except GND) and signal lines.
Figure 13.5 Example of Crystal Oscillator Circuit Connection
EXTAL2
C in
C
10 to 22 pF
in
R f
XTAL
R D
XTAL2
C out
C
10 to 22 pF
out