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rvais1's avatar
rvais1
Icon for New Contributor rankNew Contributor
7 years ago
Solved

and gate acting as or and vysa versa

hey I'm new to altera fpga , I've bought development board based on EP4CE6E22 cyclon IV and tryed to program it with basic program in quartus environment module my_and(a,b,c); input a,b; outpu...
  • ak6dn's avatar
    ak6dn
    7 years ago

    Check the logic sense of your switches and LED pins. You are assuming PUSHed=1 and not=0, and out=1 for LED on, and out=0 for LED off.

    On many/most all boards pushbuttons will be connected to a pin with a pullup, so the default input will be a '1' (high). When you push it it goes to a '0' (low).

    The LED could be driven either active high ('1' high for ON, '0' low for OFF) or active low ('1' high for OFF, '0' low for ON). Check the schematic/docs for which way on your board.

ak6dn's avatar
ak6dn
Icon for Regular Contributor rankRegular Contributor
7 years ago

Check the logic sense of your switches and LED pins. You are assuming PUSHed=1 and not=0, and out=1 for LED on, and out=0 for LED off.

On many/most all boards pushbuttons will be connected to a pin with a pullup, so the default input will be a '1' (high). When you push it it goes to a '0' (low).

The LED could be driven either active high ('1' high for ON, '0' low for OFF) or active low ('1' high for OFF, '0' low for ON). Check the schematic/docs for which way on your board.