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Altera_Forum
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12 years ago

Unused Differential I/O pins & External memory interface pins

Dear sir, I am using Cyclone -IV E FPGA in my design. This is regarding connecting "Unused Differential I/O pins & External memory interface pins" of cyclone IV FPGA E. Please read th...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
12 years ago

I typically leave unused pins unconnected and then enable the weak pull-up. This is useful on BGA devices, as it allows you to use the vias near unused I/Os as ground or power vias for via-in-pad decoupling on the bottom of the FPGA.

The problem with connecting I/O to ground is that you need to have a WARNING somewhere in the documentation not to drive unused pins to anything but ground ...

Cheers,

Dave