In The Case Of Using A Crystal Resonator; In The Case Of Not Using The Clock Pin - Renesas RZ/A Series User Manual

RZ/A1L Group, RZ/A1LU Group, RZ/A1LC Group
6.6.2

In the Case of Using a Crystal Resonator

An example of the connection of crystal resonator is shown in Figure 6.3.
Place the crystal resonator and capacitors (CL1 and CL2) as close to pins Xin and Xout as possible. Furthermore, to
avoid inductance so that oscillation is correct, use the points where the capacitors are connected to the crystal resonator
in common and do not place wiring patterns close to these components.
Since the design of the user board is closely connected with the effective characteristics of the crystal resonator, refer to
the example of connection of the crystal resonator that is introduced in this section and perform thorough evaluation on
the user side as well. The rated value of the crystal resonator will vary with the floating capacitances and so on of the
crystal resonator and mounted circuit, so proceed with decisions on the basis of full discussions with the maker of the
crystal resonator. Ensure that voltages applied to the clock pins do not exceed the maximum rated values.
Although the feedback resistor is included in this LSI, an external feedback resistor may be required in some cases. This
depends on the characteristics of the crystal resonator.
Set the parameters (of resistors and capacitors) with thorough evaluation on the user side.
Figure 6.3 Example of the Connection of a Crystal Resonator
6.6.3

In the Case of Not Using the Clock Pin

In cases where the pins are not in use, fix the level on the Xin pin (pull it up or down, or connect it to the power-supply or
ground level), and leave the Xout pin open state.
R01UH0437EJ0600 Rev.6.00
Jan 29, 2021
CL1
Crystal
R
OF
resonator
CL2
R
OD
This LSI
Xin
R
IF
Xout
R
ID
6. Clock Pulse Generator
To internal
sections
6-11