TR5-Lite User Manual
55
June 20, 2018
Chapter 5
Programmable Oscillator
This chapter describes how to program the two programmable oscillators Si570 and CDCM61004
on the TR4 board. Also, RTL code based and Nios based reference design are explained in the
chapter. The source codes of these examples are all available on the TR5-Lite System CD.
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This section describes how to program Si570- and CDCM61004. For detail programming
information, please refer to their datasheets which are available on the TR5-Lite System CD.
Si570
The Si570 utilizes Silicon Laboratories advanced DSPLL® circuitry to provide a low-jitter clock at
any frequency. The Si570 are user-programmable to any output frequency from 10 to 945 MHz and
select frequencies to 1400 MHz with < 1ppb resolution. The device is programmed via an I2C serial
interface. The differential clock output of the Si570 directly connects to dedicated reference clock
input of the Stratix V GX transceiver for SFP+ channels. Many applications can be implemented
using this function. For example, the 10G Ethernet application can be designed onto this board by
feeding a necessary clock frequency of 644.53125MHz or 322.265625MHz from the Si570.
shows the block diagram of SI570 device. Users can modify the value of the three
registers RFREQ, HS_DIV, and N1 to generate the desired output frequency.
