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Megafunction ALTIO_BUFF [output differential]: How to take output pins ?

Honored Contributor II



I am connecting counter 4-bit to ALTIO_BUFF [output differential]. Therefore 4 pin input and 4-pins output.  


But after synthesis, i am getting differential pins are all positive i.e. 8 pins am getting in pin planner. Please clarify the connection between the counter and single-ended input and differential output buff.  


Please find the attachment. and point out design error please. Anything wrong in my design
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Honored Contributor II



If you are configuring ALTIO_BUFF in differential mode & Using Stratix II, Cyclone II, Arria GX, and previous device families then you need to give that pin an I/O standard assignment with a value of "LVDS" or the differential I/O standard that you wish to use & other than these devices family, you need to port both the positive and negative signals to I/O pins.  


Please check the following links for more details, 


For Assigning Differential Pins, 


Refer Thread, 


Let me know if this has helped resolve the issue you are facing or if you need any further assistance. 


Best Regards 

Vikas Jathar  

Intel Customer Support – Engineering 

(Under Contract to Intel)