How can I simplify this circuit using boolean algebra for XOR and XNOR gates?

Click For Summary
The discussion focuses on simplifying the circuit expression M'(A'B'C + ABC') + M(AB'C' + A'BC) using boolean algebra, specifically with XOR and XNOR gates. Participants express difficulty in simplifying the ABC terms and suggest that K-maps may not yield further simplification using basic AND, OR, and NOT operations. There is interest in achieving a simplified form like (AB ⊕ C), but it is acknowledged that this may not be possible. Alternative approaches, such as using multiplexers for a more straightforward implementation, are proposed, while the complexity of achieving minimal transistor counts in chips is also considered. Ultimately, the conversation highlights the challenges and various strategies for circuit simplification in digital logic design.
speck
Messages
3
Reaction score
0
I want to simplfy M'(A'B'C+ABC')+M(AB'C'+A'BC) to as simple a circuit as possible.

I don't know the boolean algebra to simplfy the ABC terms. Help please, Speck
 
Computer science news on Phys.org
Tried K-maps?

From quick Venn inspection of (A'B'C+ABC') and (AB'C'+A'BC), I don't think you can simplify them further using AND, OR, NOT only
 
K-map is how I initial got the Eq. , right, it won't simplify with AND, OR, NOT. I want to use XOR with XNOR gates. I would really like it to simplify to something like (AB Oplus C) using XOR, but it does not. Thks, Speck
 
Does anyone think that the (A'B'C+ABC') part of the Eq. will reduce to (A Oplus B Oplus C)?
 
By simple, do you mean the least number of packages? It's trivial with a single PLA, but you'd need a burner...
 
Last edited:
I tried to put it into XOR/XNOR but I really couldn't find any way.

P.S. (I learned this stuff few weeks ago, so all I know is that there should be checkboard pattern)

Now that I said that I realized that there is infact a pattern and it is easier to isolate it when you look at it. You got to approach it differently.
See K-Map When A = 0 and C = 1
A = 1 C = 0

I get something like

A!C!(B XOR M) + A!C (M XOR B)

So far, I look at K-Map and try to isolate 2 literal K-Maps that look like XOR and "and" it with conditions like A = 1 and C = 0 .. It works so far
 
Last edited:
Another PLA-type cheater's answer: use a multiplexer. Input ABCM as the addresses, hardwire the 16 inputs to 1 or 0 to synthetise the desired logic function. The 4067 is such a 16-to-1 mux-demux and seems to be still relatively common (hey, I just feel younger!). One single package, no programming needed.

For a non-cheater answer, you'll have to wait a bit more. M and B have similar roles, as do A and C, so combining these pairs first could bring something.
 
Last edited:
(A xnor C) nor (B xor M)
please check!

It's not "the simplest" form for the number of packages on a breadboard.

In a chip, I guess it's not the minimum number of Mos neither, as an xor or an xnor needs two inverters and 8 transistors, and a 16-to-1 mux also needs one inverter per input and this function consumes 16 N-channels and 16 P-channels.

Well, this form must be the simplest in the mind of some teacher at least.
 
Last edited:

Similar threads

  • · Replies 3 ·
Replies
3
Views
27K
Replies
4
Views
6K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 5 ·
Replies
5
Views
5K
  • · Replies 6 ·
Replies
6
Views
25K
  • · Replies 4 ·
Replies
4
Views
5K
Replies
6
Views
2K
Replies
6
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K