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DGall10's avatar
DGall10
Icon for New Contributor rankNew Contributor
6 years ago

Bug fix for Quartus 13 .0 or 13.0 sp1 that fixes OR gates acting like AND gates and AND gates acting like OR gates

HI, Im using a RioRand and discovered that when I OR 2 signals either in VHDL or schematic they act like an AND gate and ANDing 2 signals acts like an OR gate. IS there a fix for this?
ak6dn's avatar
ak6dn
Icon for Regular Contributor rankRegular Contributor
6 years ago

I suspect your signal inputs are setup in the schematic as active low.

The input has a pullup connected/enabled on it, so when you push the switch it grounds the line.

Thus the normal input state is high, and it goes low when you push the switch.

So that is why you need to invert the inputs before you use them, if you want normal to be '0' and switch pushed to be a '1'.

Your LEDs can be driven as either active low or active high, so you need to figure that out as well.

I use QuartusII v13.0sp1 with a Cyclone II device all the time and it works just fine.

DGall10's avatar
DGall10
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6 years ago

Hi thank you! I was wondering if it might be that . I couldn't find where I had previously read what kind of pins they were and couldn't remember. Though I did have the weak pull up resister enabled on the button.