Quartz Crystal Placement And Signal Routing - Cypress FR81S CY91F52 Series Recommendation For Hardware Setup

3.8

Quartz Crystal Placement and Signal Routing

The feedback resistor (Rf) of the oscillator circuit is already inside of MCU device. The value of both load capacitors
(C1, C2) should be determined with crystal matching test. The crystal matching test must be done by the crystal
manufacturer based on the target board. As a result of crystal test maybe will be needed a damping resistor (Rd).
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Figure 14. Principal Oscillator Circuit
C1 10p
C2 10p
Rd
0R
Figure 15. Principal Oscillator Circuit and Startup Sequence
Document No. 002-09375 Rev. *B
Recommendation for Hardware Setup 32-Bit FR81S Family
CY91F52x
X0
Inverter
Vss
X1
16