11-13-2018 02:53 AM
I want to set 10Gbps connection between 2 evaluation board KC705 through SFP+. But I have problem.
when the optical loopback is plugged in the SFP module (a fiber connected from TX to RX), it successfully works in this rate (10Gbps) without any problem. plus +
when I decrease the rate up to 6.25Gbps in 125MHz between 2 boards connection is stabblished. But when I increase the communication rate up to 10Gbps, there is no connection. Channel and lane is zero.
I used Cisco SFP+_LR 10G and 5 meter single mode fiber optic cable.
KC705 support LR and SR, SFP modules.
Also I have checked Ibert eye diagram scan and transit is between 11%-22%. and I think this is very low. In loopback transit is between 44%-55%. have you any proposal to solve this problem?
I appreciate your time and consideration.
11-14-2018 11:06 PM - edited 11-15-2018 03:46 AM
I believe you need to tune the link for the length at 10G this can be verified with the shorter cable (1mtr) to see the connectivity at 10Gbps.
If the link look to be fine then you may need to change the Advanced parameters in the Aurora IP to match with the link performance for longer cables.
Edit1: The below image is applicable only for Ultrascale devices, not applicable for 7 series.
11-15-2018 02:05 AM
11-15-2018 02:20 AM
I believe the wizard by default shows Advanced if you scroll down in the main Core options tab (right side). If you see Advanced you need to click the down arrows at the end of Advance bard to see the options.
11-15-2018 03:39 AM
I am sorry, I believe I opened the wizard for Ultrascale and I have taken image from that. The advance options are not available for 7 series device.
For 7 series: you can enable the Additional Transceiver Control and status ports to control signals to control available for tuning at the Top module. For eg: rxlpmen, 0 -> DFE and 1-> LPM,
You can refer the UG476 for this purpose to know on the required control signals.
You may refer PG074: Page 57 for the the control signal inputs and outputs.
11-19-2018 06:17 AM
Your answer is promising. I tried this, with DFE tick removal in IBERT and 10% increase in (Open UI%) happened. And now, I have 33%-44% connection between to KC705. and 55% when I loop the fiber TX back to RX. With changing TX_precursor or postcursor, error occurs and BER increases. I think 33% is low yet and when I use this setting in Aurora, I have no connection in 10Gbps.
I appreciate your time and consideration.
11-20-2018 12:20 AM
I used 125Mhz SGMII clock as GTX reference clock (MGTREFCLK0 MGT_BANK_117). I recently read in Xilinx forums that maybe it is not suitable for GTX Transceiver in higher rates. Might be causing the problem( No connection in 10 Gbps) ? I have not Clock generator to use GTX SMA clock input pins then Is it OK using Si5324 ?
thanks a lot.
11-20-2018 02:54 AM
For 10.3125G, you may need the clock reference as suggested by UI.
As per the specific question on the Si5324 Clock, it is jitter attenuator clock, primarily used for the recovered clock purposes (Please refer UG810). I believe SMA clock input is the only option.
11-20-2018 03:05 AM
I believe you have jumpers in place for full BW:
11-20-2018 06:28 AM
When I trigge ILA with (channel_up_i), Sometimes I saw sending and receiving data between two KC705 in 10Gbps but it is not continuous and after a little time, connection will fade.
A good news is, data is correct but connection is not permanent.
Is there something wrong with my equipment?
and about jumpers, I have jumpers in place for full BW (J27 & J28) and thanks for your valuable guidance.
11-20-2018 09:36 AM - edited 11-20-2018 09:45 AM
Looks to be data getting transferred. Is lane_up and channel_up are high always once asserted.
As per the line rate, if you are using 125MHz on the both the boards they can negotiate for data with line rate calculated for the 125MHz with the same divider and multiplier of 10.3125. I believe you can achieve good link for 8Gbps with 125MHz, you can try to test the link.
11-20-2018 11:29 AM
Connection between 2 KC705 is not continous, and stable. And channel and lane is up rarely. I sent you a picture of that rare event. Then in the next run it goes down.
I must clarify, transceiver rate is 10 Gbps then 125MHz is ok for that.
Thanks a lot
11-22-2018 12:09 AM - edited 11-22-2018 12:11 AM
I changed REFCLK from SGMII to MGT SMA CLK and now I have continuous connection between two KC705.
thanks a lot for your support.
12-06-2019 12:10 PM
I am using Aurora 64 on Ultrascale+ , in framing, duplex mode, 1Lane, with logic included in the core.
I believe that the cahnnel_up and lane_up and s_axi_tx_tready are always 0 since I am not using a proper combination of settings.
Could you please suggest a proper sets of paramenters in terms of GT_REFCLK, INIT_CLK, Line Rate in order to have the Aurora Core activated and working properly ? ( I mean to have channel_up, lane_up and s_axi_tx_tready High ? )
12-08-2019 11:14 PM
you should use special MGT_CLK as GT_REFCLK,
And you must have INIT_CLK
but the line rate is up to your project.
I think If you simulate the aurora core at first, you will be in the right way.
Do not hesitate to ask if you have any questions.
12-09-2019 07:06 AM
Dear @ghasemi_r ,
thanks for the prompt reply.
So the problem was that the fpga which I am using with the FMC card connected on it cannot work at frequencies below 312.5MHz.
For that value of GT_REF_CLK everything works fine.
Do you know how the GT_REF_CLK is related to the Line rate ? There is a specific formula to compute all those paramenters? (included INIT_CLK)?
I am asking since I noted that in the Aurora core every time i set one of those paramenters the other are then computed automatically by the core.
12-09-2019 11:14 PM
you mentioned, "So the problem was that the FPGA which I am using with the FMC card connected on it cannot work at frequencies below 312.5MHz."
I think this part of your letter is not possible. you can set every line rate on some frequencies that GUI suggests.
I attached my settings as an example. GT_REFCLK is the coefficient of (Line_rate/66) but aurora 64b66b can reach the required frequency by GUI's suggestion. let me know about your line rate and your device. Maybe I can help you more.
INIT_CLK and DRP_CLK are up to you and only you must set them in GUI limitation.
12-10-2019 06:11 AM
Dear @ghasemi_r ,
my device is Ultrascale+, vcu118 xcvu9.
Line rate: 5GBps;
and on the FMC card is the model FM-S14 on which it is possible to set only 4 values of clock frequencies from user switches and those are:
212.5MHz, 250MHz, 300MHz and 312.5MHz.
12-10-2019 11:24 PM
your data width is 64 Bits and aurora adds 2 Bits for the coding issue. line rate is 5Gbps then GT frequency for the transceiver is 5Gbps/66Bits. GUI presents some frequencies but internally it will generate 5/66 for transfer data between boards.
in the figure, I set your configuration. you can use all frequencies that GUI suggest but if you have only four on your board, you can use 312.5 and there is no problem.
do not hesitate to ask if you have any questions.
12-11-2019 06:58 AM
12-13-2019 11:03 PM
you mentioned, Clocks drive GT_refclk through a switch then you are sure about the existence and accuracy of 250MHz?
GT_REFCLK must be with a lower amount of jitter. if this condition is not available GTH will not work. check the clock, please.