DF2211NP24V Renesas Technology / Hitachi Semiconductor, DF2211NP24V Datasheet - Page 659

• Manufacturer Part Number: DF2211NP24V
• Description: H8S/2200 Series, 2212 Group, USB, RTC, HSS TNP-64B; Vcc= 2.7 to 3.6 volts, Temp= -20 to 75 C; Package: PVQN0064LB-A
• Manufacturer: Renesas Technology / Hitachi Semiconductor

19.9
19.9.1
Since various characteristics related to the crystal resonator are closely linked to the user's board
design, thorough evaluation is necessary on the user's part, using the resonator connection
examples shown in this section as a guide. As the resonator circuit ratings will depend on the
floating capacitance of the resonator and the mounting circuit, the ratings should be determined in
consultation with the resonator manufacturer. The design must ensure that a voltage exceeding the
maximum rating is not applied to the oscillator pin.
19.9.2
When designing the board, place the crystal resonator and its load capacitors as close as possible to
the XTAL or OSC1 and EXTAL or OSC2 pins. Other signal lines should be routed away from the
oscillator circuit to prevent induction from interfering with correct oscillation. See figure 19.10.
19.9.3
When two or more external clocks (e.g. 16 MHz and 13 MHz) are used as the system clock,
switchover of the input clock should be carried out in software standby mode.
An example of an external clock switching circuit is shown in figure 19.11, and an example of the
external clock switchover timing in figure 19.12.
Usage Notes
Note on Crystal Resonator
Note on Board Design
Note on Switchover of External Clock
Figure 19.10 Note on Board Design of Oscillator Circuit
Prohibit
C
C
1
2
Signal A Signal B
Rev.7.00 Dec. 24, 2008 Page 605 of 698
EXTAL or
OSC1
XTAL or
OSC2
This LSI
REJ09B0074-0700