两个fpga板高速通信问题

mingyuexin · 发表于 2009-4-22 21:16:25

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不好意思，把发往英文网站的问题直接贴到这里了，希望各位不要介意哦
I'm trying to work on communication between two board A and B equipped with FPGA,440 bits data must be transfered from A to B in 3 us,
there are three lines for communication.In addition,there are 8 A boards must communicated with B simutaneously, I use DS coding to transmit,
which works at 200MHZ for communication of one A and B,but when it comes to communication of 8 A and B,it doesn't work even at 100MHZ,probably
it's because crosstalk.I don't know how to solve this problem?Anybody has solution?Perhaps I can change the way of communication,but what else
communication protocol can I use? I don't have many experiences about design of FPGA,can anybody help me to work this problem out,any suggestion
is appreciated.
PS,board A contains virtex2,board B contains virtex4,so SERDES is not suitable here.
board A has only virtex2,nothing else processor.
board B has only virtex4,nothing else processor.

szgmylove · 发表于 2009-4-23 00:39:19

期待着高手解答

mingyuexin · 发表于 2009-4-23 17:42:33

这是英文论坛里别人的回复和我的答复，我直接转到这里了
Gabor
Thank you for the reply.I'm sorry I didn't describe it clearly.
--What about data from B to A?
No data should be transferred from B to A.
--If not can you use LVDS for the interconnect?
Yes,I use LVDS for the interconnect .
If Virtex2 is the source, you can use DDR flops to drive the interface.
I will have a look at DDR flops.
--What makes you think the problem is crosstalk? Do you have adequate
--grounding on the cables?
I just think it should be crosstalk,because 8 links work at the high speed at the same time.The cables are network cables,which are not grounded.
--Are you using DCI or series resistors at the driver to reduce overshoot?
No,I didn't use any DCI or resistros.Can ou get a single link to work
reliably?
I just did the test in only B board,which means B sends and B receives it back.
For one link,it workes reliably.
But for more than one link,it doesn't work,the received data is wrong.when I do post simulation in questasim,more than one links receiver have unknown state.even if I reduce the speed to 100 MHZ,I don't know why.