Stratix IV GX dev kit

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I am looking at buying the Stratix IV dev kit. It comes with 8 transceivers routed to SMA connectors, but I need 16. Is it feasible to (with a decent performance) synchronize two of this boards by using the clock input/output?

Any other thoughts on what to use to get this 16 transmitters working?

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You mean the Stratix IV SI kit?

You can also use the Stratix IV GX development kit. It has two HSMC connectors with 8 + 6 transceivers, and then the PCIe edge connector with another 8 transceivers. Samtec sells cables for HSMC-to-SMA breakout and for PCIe-to-SMA breakout.

The DE4 kit could also be used.

Cheers,

Dave

Thanks for your quick answer Dave!

Regarding Stratix IV GX dev kit, problem is that the reference manual quotes 12 channels with 8.5 Gbps + 6 with 3.5 Gpbs (I don't know why). That is in page 2-5. I would like all of them to have the same performance. I am also not sure about the PCI: can I just use that physical interface but custom configure the transceivers?

The DE4 is a little bit of the same: it quotes only 12 transceivers available.

http://www.terasic.com.tw/cgi-bin/page/archive.pl?language=english&categoryno=138&no=501&partno=2

So I still don't know what to do. Am I reading any of this availability in a wrong way?

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Regarding Stratix IV GX dev kit, problem is that the reference manual quotes 12 channels with 8.5 Gbps + 6 with 3.5 Gpbs (I don't know why).

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Let me look at the schematic ... p8 has the transceiver connections on the FPGA. The transceivers are all connected to true transceiver channels, not the 6.5Gbps CMU channels, so they are all capable of 8.5Gbps. Its possible that they don't want to 'quote' that due to the layout. I've been using the HSMC connections at 5Gbps without issues.

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I am also not sure about the PCI: can I just use that physical interface but custom configure the transceivers?

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Yep, you can configure it to do what you like. The only caveat is that the transmitters have AC-coupling caps on them. If you needed a DC connection, you could replace them easily enough.

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The DE4 is a little bit of the same: it quotes only 12 transceivers available.

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I don't have one of these, so you'd just have to look at the schematic and see what they've routed. Chances are they are not quoting the PCIe interface transceivers in that list, since they assume you'll want to use the board in a PCIe slot. However, both boards work fine standalone on the bench.

Cheers,

Dave

"can you give more information about what you're trying to do?"

what I want to do is to have 16 high speed transmitters that I am going to use just as high speed serializers with around 5 Gbps max rate (protocol in Basic mode, all the blocks bypassed, only a high speed serializer per channel going on). The only requirement is that I need all of them to be synchronized (and that I might need long chains of 1's or 0's, so it will be DC coupled, but that should not have anything to do with this).

"and though its still early and ES, have you looked at the SV SI kit? "

yes, but again it does not have 16 channels routed through the same interface, which would be preferable. However, based on what you are saying, I might have to deal with that anyway.

Ok, so regarding the stratix IV (or even de DE4), suggestion would be to use the HSMC with maybe the samtec arrangement to sma, and the PCI to sma too. All that would allow to have all channels with the same performance and synchronized? What I don't like as I said is the complexity of having two or three different adapter boards - connector interfaces - etc, but it looks like the only way to get 16 channels to work.

Any thoughts about synchronization of 2 Stratix IV GX with the 8 SMA transceivers?

Thanks a lot!

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"can you give more information about what you're trying to do?"

what I want to do is to have 16 high speed transmitters that I am going to use just as high speed serializers with around 5 Gbps max rate (protocol in Basic mode, all the blocks bypassed, only a high speed serializer per channel going on). The only requirement is that I need all of them to be synchronized

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Synchronous, or synchronized?

The channels will all be synchronous, because you can use a common reference clock. However, there is no guarantee the serial data streams from transmitters are time-aligned (synchronized).

What exactly are you trying to do?

Cheers,

Dave

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Any thoughts about synchronization of 2 Stratix IV GX with the 8 SMA transceivers?

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I use the clkout_sma on one board to send its reference clock to a second board. The transmitters on one board route to receivers on the second board. The receivers start off in lock-to-reference mode, and then switch over to lock-to-data mode to capture the data from the transmitters.

You need to ensure that the transmitter data stream has enough toggles so that the lock-to-data logic at the receivers work. You can use a PRBS sequence at the transmitter to modulate data, and then a PRBS sequence at the receiver to demodulate. When you power-up, you first have to synchronize the PRBS generators between boards, and then enable transmitter data.

Cheers,

Dave

Dave,

I just want to use the 16 channels as serializers: output 16 parallel arbitrary sequences of bits that will be stored in memory in the FPGA. There will be no receiver, and there is no protocol involved. It is just a serializer. This will be used to test a piece of equipment that I have.

The reason to use transceivers is that I need to have the ability of precisely align the edges of the 16 channels (in the subnanosecond range), and for that I need the very high frequency clock that the transceivers provide. Those edges have also to be sinchronized between them (if two transitions should happen at the same time, they cannot happen 1 ns apart). I understand that there is no output feedback / pll that guarantees that they will be synchronized, but hopefully there will be minimal variation between channels if they are all locked to the same clock (I hope in the low picosecond range). That obviously depends on how the internal hardware design, but I would expect them to be almost identical.

Does that make sense?

I am sorry if I am not been able to clearly explain what I want to do; it is really very simple but I find it hard to write it down.

Thanks,

Miguel

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Does that make sense?

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If you want the same sequence on all 16 channels, then you might be better off using an RF splitter.

If you want different sequences on all 16 channels, then you will have to use multiple transmitter channels.

You should be able to enable data synchronously across channels, and if you can't, if you can tell they are misaligned, you can always insert a bit-slip component that shifts the serial stream 1-bit at a time.

Cheers,

Dave