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R20UT4084ED0130 Rev. 1.3
2020-05-12
Chapter 4 Clock sources
External crystal oscillators for the device clock supply are provided with the
board.
4.1.1
MainOsc
A crystal or ceramic resonator can be mounted on socket X1.
A 20MHz and a 40MHz oscillator are supplied with the board.
The signals X1 and X2 are by default not connected to a pin header in order to
minimize disturbance on the resonator signal. If needed the signals can be
connected to CN5 (pins #24 and 26) via connecting with 0Ohm resistances R48
and R49. For details, please refer to
.
4.1.2
Programmable Oscillator
It is possible to mount a programmable crystal oscillator on the PiggyBack board
at OSC1. The available footprint and circuitry is designed for a SG-8002CE
programmable crystal oscillator from Epson Toyocom. The output from this
oscillator can be connected to port X1 via resistor R38. The SG-8002CE is
neither mounted nor provided with the board. For details about the available
circuitry, refer to
. A resonator mounted on socket X1
must not be used in parallel to another clock source.
