I am trying to get into a bunch of stuff by taking on a large project. I want to create my own FPGA board, for which I am trying to understand the schematics of an available board (In this case a Cmod A7).

The IC has a shaded band on it's edge next to a group of pins. What does this notation mean? I also think that these schematics may have been created using Altium, to which I don't have access.


Also hopefully, someone can confirm if the bidirectional arrows next to the IC symbol are inout pins.

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    \$\begingroup\$ Based on what I know about FPGAs, I would guess that the shading denotes programmable pins, while the unshaded pins have a fixed function. \$\endgroup\$ – Dave Tweed Nov 11 '16 at 12:59
  • \$\begingroup\$ Is the shading the same color here as for other groups of pins? It looks likely they shaded those pins with one color to indicate they're all in the same IO bank. \$\endgroup\$ – The Photon Nov 11 '16 at 15:35
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    \$\begingroup\$ The shading is purely graphical, to make the design easier to read. It has no meaning to the tool. \$\endgroup\$ – The Photon Nov 11 '16 at 15:36

I asked a helpful staff member over at Digilent (makers of the Cmod A7 board) - and have just received this reply on their support forum:

The colored pins are for bank identification. It is done for organizational reasons. And the bidirectional arrows next to the IC symbol are i/o pins. Hope this helps!

Edit: I goofed up with my original answer trying to paste from the datasheet on an iPad. Not only was my formatting wrong, but my answer was too. Sorry about that :(

| improve this answer | |
  • \$\begingroup\$ Thanks for the edit, @Wesley-Lee – was struggling on a tablet :) \$\endgroup\$ – Sean D. Sollé Nov 11 '16 at 19:09
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    \$\begingroup\$ Thank you! For some reason I didn't think of asking in the Digilent forums. \$\endgroup\$ – kchak Nov 12 '16 at 4:52

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