Honored Contributor
Honored ContributorThe manual for the transceivershere (https://www.altera.com/content/dam/altera-www/global/en_us/pdfs/literature/hb/cyclone-iv/cyiv-52001.pdf) says on 1-14:
disable oct to use external termination if the link requires a 85 ohm termination, such
as when you are interfacing with certain pcie gen1 or gen2 capable devices. On top of that there is: if you disable the oct, then you
must externally terminate and bias the receiver. ac-coupled links are required for
pcie (...) The problem is: I don't care if it works with just AC coupling caps (and I know that it does). I need an official source that states that this way of wiring PCIe is correct and supported. Unfortunately the document (as written above) states, that an external termination is used for PCIe. I won't be able to justify a circuit design that contradicts with the manual. The manual clearly says: 1. Disable internal Termination (OCT) for PCIe 2. Transceivers must be biased externally if internal termination is disabled If I get something really wrong here, please tell me. Otherwise I must refrain from using an Altera chip in my current project. The current development is done on a Terasic Dev-Board and works with just AC coupling and disabled OCT. But it contradicts with the manual and therefore I won't be able to justify this design in front og my higher-ups.
