2 bit comparator-adder-subtractor with two values

Thread Starter

74266

Joined Mar 20, 2016
41
Hello everyone I would like to ask if someone know how to make a 2 bit comparator-adder-subtractor with two values
for this project there must be 4 seven segment 1 is for the command which is comparator-adder- subtractor, 2 is for the two values,and the last is for the result.
Next for the display of the command 0 is for NOP(no operation),1 is for compare,2 is for add,3 is for subtract. The display values is only up to 0-3. And the final result value is only up to -3 to 6. I know the basic of adder,subtractor,comparator and seven segment its just this kind of project is kinda to complicate for me right now that why I would like to ask for help for this .Also for negative you will use dot(h)

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absf

Joined Dec 29, 2010
1,942
First you'd need a 74HC139 for decoding the 2 bit instruction to 4 action lines for the compare, add & sub logic...

Is this home work of some kind? When is the dead line?

Allen
 

Thread Starter

74266

Joined Mar 20, 2016
41
Our project requirements must only use basic gates which is 7408(AND), 7404(NOT), 7432(OR),7486(XOR),74266(XNOR),7400(NAND) and 7402(NOR)
OUR project deadline will be tomorrow so It would be nice to finish before the afternoon tomorrow here
 

absf

Joined Dec 29, 2010
1,942
Our project requirements must only use basic gates which is 7408(AND), 7404(NOT), 7432(OR),7486(XOR),74266(XNOR),7400(NAND) and 7402(NOR)
OUR project deadline will be tomorrow so It would be nice to finish before the afternoon tomorrow here
OK, then do you know how t0 make a 2_to_4 decoder using the gates that you mentioned?

See page 1 of the datasheet attached. You dont need the enable function of the chip. So to make the 2 to 4 decoder, you need a 7400 and a 7404 (4/6) chips.

Allen
 

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