Cyclone V: Set LVDS output buffer delay

Hello everyone,

I have an application where I'd like to compensate board trace length differences using (fixed) output delays. The outputs are driven by the dedicated SERDES hardware with an LVDS I/O standard. I have set the assignments like this:

set_instance_assignment -name OUTPUT_BUFFER_DELAY 119 -to IO_B4A_B52_AG14_P

IO_B4A_B52_AG14_P is the name of the positive LVDS output pin. This looks fine, but the fitter complains:

Error (169226): I/O standard LVDS on pin IO_B4A_B52_AG14_P cannot have Output Buffer Delay logic option setting 119

Is it impossible to set output delays for LVDS buffers? Or do I need to assign them in some different way?

Thank you!

Best regards,

Philipp