4 Channel NOT and AND Gate Symbols

Question

I am designing an ALU for my computer architecture class. The rubric states that we need to simplify each logical part to make it as clear as possible. My group condensed the 4 NOT gates and 4 AND gates into their own components which are still represented using the NOT and AND gate symbols.

Question: Using the AND and NOT gate symbols, is it correct that they have multiple outputs? Or should their symbols now be rectangles with a title because they are a 'non standard' component?

Before

After

EDIT: I had to remove the entire schematic images because this assignment isn't due yet and other teams could potentially cheat. I hope this is still helpful!

Answer 1

You shouldn't do that.

An AND gate with 4 inputs is a standard symbol. But it only has one output, which is high only if all 4 inputs are high. If you draw a 4-input AND gate and intend it have some other function, you're just going to confuse people.

With your AND gate with 4 outputs, how am I to know which inputs must be high for each output to be high?

And if you want to unclutter a drawing by removing NOT gates, you can do it by using bubble notations on the inputs of whatever those NOT gates drive, not by inventing a new 4-channel NOT-gate symbol.

Answer 2

There are some circumstances in which what you're doing might make sense. But give your symbols buses for the inputs and outputs, rather than individual pins. Then it becomes a bit more clear that the output is a bit-for-bit AND of the two inputs.

It would be the diagrammatic equivalent of writing the following in, say, Verilog:

wire [3:0] a;
wire [3:0] b;
wire [3:0] c;
wire [3:0] d;

assign c = a & b;
assign d = ~a;

If done this way, I think most people would get what you intended.