# 2-Bit Registers using D Flip-Flops HELP!!!

#### glitterized_dreamz

Joined Feb 13, 2007
6
Here's the problem:

There are three 2-bit registers A,B, and C. Design the logic to perform:

AND: C <-- A "and" B
OR: C <-- A "or" B

And and Or are control signals and each bit in the register is a D Flip Flop.

The answer requires illustration, so you can send me the answer via email if you'd like: glitterized_dreamz@hotmail.com
Any help would be greatly appreciated, I've been stuck on this one question for hours and I can't find a single website that talks about this small problem.

#### Papabravo

Joined Feb 24, 2006
20,404
Here's the problem:

There are three 2-bit registers A,B, and C. Design the logic to perform:

AND: C <-- A "and" B
OR: C <-- A "or" B

And and Or are control signals and each bit in the register is a D Flip Flop.

The answer requires illustration, so you can send me the answer via email if you'd like: glitterized_dreamz@hotmail.com
Any help would be greatly appreciated, I've been stuck on this one question for hours and I can't find a single website that talks about this small problem.
This is pretty straight forward. You need a two input AND gate for each bit and a two input OR gate for each bit. The outputs of these gates go to a multiplexer, which based on the control signals selects either the AND output or the OR output. You need to decide what happens if neither control signal is active and also what to do if both control signals are active.

#### glitterized_dreamz

Joined Feb 13, 2007
6
That's one way to build it, but my solution has to involve d-flip flops. Thanks for the respsonse though.

#### Papabravo

Joined Feb 24, 2006
20,404
That's one way to build it, but my solution has to involve d-flip flops. Thanks for the respsonse though.
That's nice, but D flip-flops cannot do the required logic so good luck with the sisyphean task of pushing that particular rock up the hill. I think you have misinterpreted the requirements since the D Flip-flops are obviously involved in realizing the three 2-bit registers