cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 
Contributor
Contributor
819 Views
Registered: ‎11-24-2009

Unused MGT Pins on existing board

Hello,

 

We've had a Spartan 6 Board in production for some time that has been working well.

 

We would now like to do a run of these boards where the transceiver function is no longer required.  This means that the MGTRX pins will be floating with a blocking capacitor to an empty pad.  The guide advises that unused MGT RX pins are connected to ground; but we'd really rather not make any changes to the board if possible.

 

1: Would there be any issues with leaving the RX pins floating and the MGT bank powered?

 

2: Can I leave the rx pins floating and configure RCV_TERM_GND=True and configure RCV_TERM_VTTRX=False to give the RX pins a path to ground through the FPGA?

 

3: I can also remove the power supply to MGTAVCCPLL MGTAVCC, MGTAVTTRX and MGTAVTTTX.  The receive pins would still be floating however.

 

I'm of course open to any other suggestions on how best to proceed.  Any advice that you could offer on this would be greatly appreciated.

 

Cheers,

Pete.

0 Kudos
Reply
1 Reply
Xilinx Employee
Xilinx Employee
722 Views
Registered: ‎06-30-2010

Have you looked at UG386, in there we deal with unused GTs: http://www.xilinx.com/support/documentation/user_guides/ug386.pdf page 165 has the details
-------------------------------------------------------------------------
Don’t forget to reply, kudo, and accept as solution.
-------------------------------------------------------------------------
0 Kudos
Reply