what can i do if i want that the displays show a negaive number in a 7 segment displays?

Thread Starter

Sebastián Gómez 1

Joined Dec 5, 2016
i 'm making a circuit of Adder/Substractor in 1's complement, the objective is put the answer in 7 segment displays. I have at least the 75% of the circuit made, how you can see in the attached image, the only problen that I have is that in the output (7 segments displays) doesn't show the negative numbers. For example, if i have 1-2=-1, that means that in binary will be S(1) M(0001) -> (10001). the circuit literally do the binary number, i mean, instead of show -1 (1 0001) it shows 17 (10001) what can i do if i want that the displays show -1?



Joined Mar 31, 2012
If you are doing 1's complement, you need to first define what the width is since all of the binary representations that deal with negative numbers are fixed width.

It sounds like you have a 5-bit representation. If so, how do you know if the value is positive or negative? If it's negative, then how do you determine the positive value that should be displayed?

Try to answer these questions based on the definition of 1's complement. If you can, then how to manipulate them should be pretty straightforward.