Xilinx VC709 Si570 Programming page 21

VC709 Si570 Programming
For this example, Si570_0 will be reprogrammed from 156.25 to 200
MHz
– This requires use of the SiLabs Programmable Oscillator Calculator
To use the SiLabs calculator, the correct fXTAL value for each Si570
must be determined, using this equation:
For this equation,
– Fout = 156.25, the preprogrammed frequency of the Si570s on the VC709
We need to determine:
– RFREQ
– HSDIV
– N1
These can be found be reading back the registers on the Si570
Note: Presentation applies to the VC709