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sroehrig's avatar
sroehrig
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5 years ago

Stratix 10 GX: H-Tile Transceiver - *Direct* dynamic reconfiguration

Hi all, I am trying to use the "Direct Reconfiguration" flow with a self-coded controller/state machine using the reconfig_* signal interface as referenced in chapter 6.7 of the "L- and H-Tile Tra...
Deshi_Intel's avatar
Deshi_Intel
Icon for Regular Contributor rankRegular Contributor
5 years ago

Hi,


  1. Do you performed recalibration at the end of reconfiguration process ?
  2. Also, what pre-emphasis value that you change on the fly ? Did you try out few value or compare min, middle and max value to see if there is a difference ?
  3. For the sake of experiment, you may want to start with VOD setting to see more obvious signal eye changes
  4. Are you using oscilloscope to measure the signal eye ? Have you double check to ensure you have setup the eye diagram measurement setting correctly ?


Thanks.


Regards,

dlim


sroehrig's avatar
sroehrig
Icon for New Contributor rankNew Contributor
5 years ago

Hi dlim,

Thanks for your answer and suggestions.

1. No, I don't perform re-calibration. The documentation says that re-calibration is necessary when the data rate or protocol mode is changed. So I thought that this isn't necessary when "only" the analog PMA settings are changed. Anyway, I will try to add this to my control sequence.

2. We changed through pretty much the complete valid value range in the lab. Of course, especially we tried a few changes from min to max values. But there is absolutely no visible difference, so I really guess that the change is not "propagated" to the actual high-speed driver stage although the changed values can be read back from the reconfiguration interface.

3. Also here, we tried changing from min to max VOD setting only. And there is no visible difference in the eye of the output signal.

4. Yes, we use an oscilloscope. The setup is definitely fine. We have used the "Board Test System" software initially with the "qts_fmca" design to verify that the programming and control of the FPGA from the PC side works as expected. Here we can see changes on pre-emphasis and VOD propagating directly to the signal eye.

Additional note:
My answers to points 2-4 aren't 100% true. We actually have the "Stratix 10 GX FPGA Development Kit" board and use the following signal chain:

Stratix 10 Transceiver PHY TX -> FMC-A -> Electrical-2-Optical Board from another supplier -> Optical cable -> Optical-2-Electrical Board from the other supplier -> SMA connector -> Oscilloscope

With the oscilloscope we look at the actual waveform of the received signal AND we measure the eye diagram.

So we can't see the Transceiver PHY TX output directly at all. At the moment we don't have an FMC->SMA adapter board, so there is no possibility to probe the TX output signals directly.

BUT: as I wrote, we have used the related "Board Test System" example design as a first shot and could see direct influence of the analog TX settings to the eye measurement results. As of now we can't see any (even slight) influence of any setting changes that I do via my self-coded reconfiguration controller.

Again, I appreciate any comments/helpful tipps very much.

Best regards.
Sebastian