I was confused by the Pin Planner. who can help me

Question

Hi, Friends.

In my design. I use 8 pins for address input. they are AC8 to AC15.

after I assignment them, I find in Pin Planner that there are pins named by AC8~~AC15 and pins named by AC[8]~~AC[15].

why are the additional pins added? are they usful?

and why do the direction of AC* differ from that of AC

[*]?

In fact, I reserved the pins of AC8~~AC15 as input tri-state. but after I compile the design again, the direction turn to be OUTPUT?

It confused me!

thanks.

altera_forum · Answer

Most of io pins support lvds. So each pin is two physical pins(+,-) . Can it be just that ?

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