Notes On Configuring The Oscillation Circuit - Renesas R-IN32M4-CL2 User Manual

R-IN32M4-CL2 User's Manual: Board design edition 3. Clock Input Pins
3.2

Notes on Configuring the Oscillation Circuit

As the R-IN32M4-CL2 includes an oscillation block, oscillation circuits are easily configurable by externally connecting
a resonator and components for external constants. Though configuring an oscillation circuit is easy, the configured
circuit is analog and operates at a high frequency, so notes that differ for logic become applicable.
To achieve stable operation of the oscillation circuit, set components for external constants to the optimum values
(capacitors on the input and output sides, and limiting resistors) and observe the following points required for an analog
circuit.
・Place the oscillation circuit near the R-IN32M4-CL2.
・Place the oscillation circuit as far as possible from high-frequency input pins such as clock pins.
・Place the resonators and components for external constants immediately close to the input and output pins of
oscillation circuit, and keep the connections as short as possible.
・Make the ground connections of the capacitors to the GND pins of R-IN32M4-CL2 as short and thick as possible.
・Make the lead wires between the resonator and capacitors as short as possible.
・Surround the components for external constant parts by as much GND wiring as is possible.
OSCTH
R-IN32M4-CL2
XT1 XT2
Board
GND pattern
Figure 3.1 Example of GND Pattern for the Components for External Constants
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Dec. 28, 2018