02-25-2019 12:48 AM - edited 02-25-2019 04:46 AM
I'm trying to realize following type interface using SERDES primitives. FPGA B is a copy of FPGA A. But when I try to implement the scheme, I get from Vivado following critical warning and errors. As I understand is related with try place SERDESE primitives in the same IO bank, but clocking scheme does not allow it?How should I change my schema to get the specified implementation?
02-26-2019 02:37 AM - edited 02-26-2019 02:38 AM
The correct Bidirectional Signaling Using IDELAY/ODELAY with ISERSDES and OSERDES is as follows.
The clock and clock_Div inputs to the ISERDED and OSERDES should be from common source.
02-26-2019 02:41 AM
Are these of use as reference
02-26-2019 05:05 AM
02-26-2019 06:25 AM
Is the data rate different in transmitting from FPGA A to B and Vice a versa?
02-26-2019 10:34 AM
02-26-2019 11:42 AM
02-26-2019 10:53 PM
Maybe I did not understand you correctly. But it seems to me that SLK21 is not needed in this case? I can not understand: the 7 series allows you to use different sources of clock frequency for ISERDESE and OSERDESE. In this case, I can not do this.
02-27-2019 02:12 AM
To use source syn clocking,
your Iseddes needs to be clocked by the received clock,
not certain thats possible in the chip you have, give it a try.
typical , high speed buses use i and o serdes, and these tend to be uni direcional , so they can have termination ,
so your in a bit of a un usual place here.
02-27-2019 02:53 AM
Following from the UG and picture above, I can not use received clock for iserdes clocking. Does this mean that I basically can not implement the required scheme? As in this case, for example, implemented memory interfaces that allow bidirectional data and a clock?
02-27-2019 08:00 AM
What do you want to do ?
Interface between FPGAs as you have shown , or FPGA to DDR memory ?
If DDR memory, then use the memory wizard, there are special pins and functions to cover that you have to use, special track constraints, tracks you have to feed out fomr the FPGA to the DDR and back and the DDR chips have active / switched temrminatoin and PLL's on them.
If FPGA to FPGA, then, if you want to send stuff source syncronous, then you have to have clock with data, thats the definition of source syncronous. Else use another method.
There are many other options out there to connect two FPGA's together, the current favorit is to use the GTx phys on th echips to run serial links at Gb/s ,
02-27-2019 10:11 AM
I need Interface between FPGAs. But I do not understand how to send clock from FPGA 2 to FPGA 1. Because both ISERDESE and OSERDESE of FPGA1 and FPGA2 most operate with the same clock. This clock generate MMCM on the FPGA1 side, connect to ISERDESE and OSEREDSE in FPGA1 and this clock send to FPGA2 where this clock signal connect to ISERDESE and OSERDESE also. My question is what for send clock from FPGA2 to FPGA1? WHAT this signal will be clocked?Who will use it? After all ISERDESE and OSRDESE on the FPGA1 side use MMCM clock, they do not need transferred from FPGA2 clock?