Honored Contributorin datasheet,i find maybe it isn't similar to use LVDS in Cyclone1,cyclone2,and cyclone3,
so what can i do if i want to use LVDS? 1,does it need resistor? 2,how many wire i need ? in my opinion there is two way to do this the one is two wire and use CDR, and the other is four wire use two to send data ,and two as clock reference. can you tell me the trues? thank u
Honored Contributorand in xilinx there is no need to use resistor?
Honored ContributorHello stephenzhou. Yes, you should use external resistors in Altera and Xilinx.
I'm going to use LVDS too. And I have some questions. I have a devboard from Atmel with LVDS outputs and I want connect it with my Cyclone board. In datasheet I have read, that Atmel board has 100 Ohm termination resistors. So I can connect it directly to Cyclone pins. But distance between resistors and Cyclone device is very long( much longer, than recomend Altera). Will be it work? Can it damage chips?Honored Contributorin my opinion,it will not damage chips.
and in datasheet the long u use the speed will go slowly. U can try it. good luck! and i want to ask u how many wire do you use ?Honored ContributorI will try :-) Now I use 18 wires (8 bit data and 2 wires for clock). But in future I'm going to use 16 bit data bus.
Note: CycloneIII has dedicated output buffers for LVDS so no external resistors required.Honored Contributoru didn't use encoder for CDR?
and it just use 16 wires for 8bit! and good luck!Honored ContributorI use 16 wires, because Atmel DSP board transmit 8 bit per clock at very high speed. You can serialize your data and use only 4 wires.
Honored Contributorthank u NICK.
What u said 4 wires ,just 1wire for data 1 wire for different data ,1wire for clock 1wire for clock?Honored ContributorYes. Differential pair for data and differential pair for clock. I successfully used this circuit. Also you can try to use 3-wire circuit, as you wrote in first post.
Honored Contributor3-wire?
may be 2 wire and data with clock in CDR.Honored ContributorYes, you are right.
