Altera_Forum
Honored Contributor
8 years agoCyclone V ALTLVDS_RX clocking
Hello all,
I am looking for some help trying to achieve a bank-usage-optimized pin assignment for a design. I need to receive data from 4 different LVDS interfaces in a Cyclone V GX C9 FPGA, where each interface need to use a dedicated corner FPLL, that is, using the 4 FPLLs available in the FPGA. According to the Cyclone V Device Handbook, there are restrictions regarding the use of fractional PLLs that drive LVDS receiver channels. Specifically, three of these restrictions are:- The corner fractional PLLs can drive the LVDS receiver and driver channels. However, the clock tree network cannot cross over to different I/O regions. For example, the top left corner fractional PLL cannot cross over to drive the LVDS receiver and driver channels on the top right I/O bank.
- You must use the dedicated reference clock pin of the same I/O bank used by the data channel.
- Each PLL can drive all the LVDS channels in the entire quadrant.