1649 - LatticeECP2/M: Should the LatticeECP2/M SERDES PLL band be manually set to band 2 for PCI Express application?

1649 - LatticeECP2/M: Should the LatticeECP2/M SERDES PLL band be manually set to band 2 for PCI Express application?

It is better to limit the PLL band searching range and enable auto band searching to account for extreme process variations.  If you use ispLEVER 8.1 Service Pack 1 or earlier software, you can add the following into your PCS config text file to limit the band to 5 and lower, and guard against possible incorrect band selection

vco_band_threshold "0101"

If you use Lattice Diamond software, this is automatically handled by the software.