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Explorer
Explorer
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Registered: ‎12-01-2010

GT Transciever RX Data Valid signaling

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I am attempting to understand the functionality of the GT0_DATA_VALID_IN signal on the FPGA Transcievers Wizard wrapper.  The Product Guide (PG168) barely touches on this (on pages 29 & 30).  Below is the relevant info.

 

 

The example design defaults FRAME_CHECKER as data_valid. You can identify your data
valid indicator and provide the necessary hysteresis on this signal to avoid a false
indication of data_valid. Data valid is only used as an indicator to monitor the RX link.
You need to customize the data valid indicator based on your system design.

 

Data_valid_chain.jpg

 

So it is my understanding that the example design will check frames and then indicate to the RX block that the data is valid?  I don't follow.  What does the receiver care if the data is "valid" or not?  It has no control over the incomming data one way or another.  I would like to tie this signal off, as i don't forsee using it.  Can it just be a static 1 to essentially bypass the monitoring?  Is this good practice?  What's the "correct" way to deal with this signal?

 

Thanks in advance.

 

 

(Vivado 2014.3, 7 Series FPGAs Transceivers Wizard v3.4)

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Explorer
Explorer
15,311 Views
Registered: ‎02-22-2010

Re: GT Transciever RX Data Valid signaling

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You can certainly tie GT0_DATA_VALID_IN to '1'. This is how I implemented.

 

I think that the example design suggests a way of checking that the GT CDR is locked by tracking the incoming data stream.

 

Regards,

Eze

 

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Highlighted
Explorer
Explorer
15,312 Views
Registered: ‎02-22-2010

Re: GT Transciever RX Data Valid signaling

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You can certainly tie GT0_DATA_VALID_IN to '1'. This is how I implemented.

 

I think that the example design suggests a way of checking that the GT CDR is locked by tracking the incoming data stream.

 

Regards,

Eze

 

View solution in original post

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Moderator
Moderator
8,398 Views
Registered: ‎02-16-2010

Re: GT Transciever RX Data Valid signaling

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You can connect don't_reset_on_data_err signal to 1'b1 and make this signal does not restart the Rx_startup_fsm.
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