I'm using cyclone v "5CGXFC5C6F23I7N" .I'm interfacing external optical receiver to cyclone v transceiver, here our OPTICAL RECEIVER(supply voltage 3.3V) is "CML" standard but cyclone v TRANSCEIVER supports "PCML"(1.2 V PCML, 1.5 V PCML, 2.5 V PCML).
1)Can i connect CML to PCML standard? if yes,which PCML (1.2 V PCML, 1.5 V PCML, 2.5 V PCML) should i connect?
As I understand it, you have some inquiries related to the interfacing CV XCVR with third party device's IOs. For your information, you will need to cross check the CV XCVR specs vs the third party device IOs to ensure they are compatible. You may refer to the "Receiver Specifications for GX, GT, SX, and ST Devices" and "Transmitter Specifications for GX, GT, SX, and ST Devices" tables in CV datasheet for further details. As for the IO standard, CV TX only support 1.5V PCML. You may select the same for the CV RX. Note that for the receiver, the specs in the table applies to all the support IO standards ie 1.5 V PCML, 2.5 V PCML, LVPECL, and LVDS.
Please let me know if there is any concern. Thank you.