AR# 36320: Virtex-6 - N-side pseudo-differential output driven by OSERDES does not toggle
Virtex-6 - N-side pseudo-differential output driven by OSERDES does not toggle
When I use an OSERDES to drive an OBUFDS forpseudo-differential output, I see the P-side can be toggling as expected while N-side does not.
If I replace OSERDES with an ODDR or replacepseudo-differential I/O standards with LVDS, then both P-side and N-side can work fine. Does Xilinx FPGA supportpseudo-differential output driven by an OSERDES?
This is Bitgen software issue, rather than a silicon issue.
This issue is fixed in ISE 12.2 software. Another workaround would be toreplace the OBUFDS with an OBUFTDS, connect the TQ output of the OSERDES to the T input of the OBUFTDS,and tie T1-T4 to ground on the OSERDES. Note that simply grounding the T input of the OBUFTDS will not work.