I'm uising arria V device in my project, a pair of LVDS pins are used in my design, which are configured as output. It always cannot work well, and by using OSC I watched the output waveform of LVDS port, it was quite strange, the pos and neg pins are the same, and even the Vocm and Vdm is incorrect, refer the below image. I'm sure the pin configuration is accurate, and the pins is not demaged since I tried another LVDS pin. So, whats could be the reason? thanks
Hello,, sorry for delay in response.
There should be common mode voltage in the LVDS bus which i didnt see in the graph you sent me.
can you check the LVDS std is set correctly ?
Sorry , I am not sure what is missing here.
Can you check is IO is not open ended ? Pretty much looks like other side is open.
Is there any external termination ?
Thank you ,