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Need help with assignment using Quartus II

kc212

Mar 17, 2011
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Need help to convert hex code to binary using NAND logic in Quartus II

Hello everyone. I have been given an assignment for my Digital Electronics class and I'm having trouble figuring out how to do this. I am really new to this stuff so it might be really simple but it's giving me a hard time and the Professor wasn't really much help.

I have to develop the logic circuitry necessary to meet the following requirements:

Develop the NAND logic for a Hexadecimal keypad encoder that will convert each key closure to binary.

Design the circuit to produce the output binary code and simulate it's operation using Quartus II.

I really have no idea where to start and he said that I must use a NAND gate to produce the output. Can anybody give me some advice as to where to start and explain to me what is being done? I would really appreciate it I'm stuck. Thanks.
 
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(*steve*)

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The first thing you need to do is figure out how to make NANS, NOR, AND, OR, inverters etc using just NAND gates.

Then set up a truth table that shows which output bits must be set for each input (there may be 16 -- but it depends on your keypad).

Then for each output bit, determine logic that will produce this from the input bits.

Then use the stuff in the first step to convert that to NAND gates.

Then simplify things, because you will probably have redundant gates (e.g. three inverters in a row)

Then enter this into your software and verify that it works.

You may want to do it in stages -- for example, just model one bit at a time.
 
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