Puzzle #10 - Mux Logic
September 15, 2007Your company is pretty tight on budget this year and it happens to have only Muxes to design with.
You are required to design a circuit equivalent to the one below, using only Mux structures.
Adventures in ASIC Digital Design
Tricks and Tips for ASIC Digital Designers
Your question is cute, but Muxes are not really the best choice for a design house with a tight budget.
Muxes are the nightmare of every router developer. The pin-density on a mux is high, so most detailed routers dont do a good job with wide muxes.
If you have a giant mux, you are almost better off designing it like you would design a datapath block.
-RN
It is a puzzle!
Sometimes we impose certain restrictions to have a nice puzzle with the solution we want. That is the whole idea.
I never claimed using muxes is the best way for this design.
Mux equivalent for Ex-OR,AND n or gates r is str8 forward…for a simple FF implementation with muxes here u go…http://ieeexplore.ieee.org/iel4/5474/14742/00669513.pdf?arnumber=669513
Am I allowed to use logic-1 and logic-0?
Thnx
/MB
Yes.
how far can you get without ???
I’ll take a shot. My solution assumes we can use Q and ~Q, which would eliminate the need for C.
There are 3 muxes.
1st mux: Has ~Q as input for select 1 and Q as input for select 0, with A as the select.
2nd mux: Has 1 as input for select 1 and A as input for select 0, with B as the select.
3rd mux: Has the output of the 2nd mux as the input for select 1 and 0 as the input for select 0, with the output of the 1st mux as the select.
The output of the 3rd mux is the output of the circuit.
Did you mean that you have Q and QB available already from a flip flop?
The flop was one of the elements that was supposed to be implemented using muxes…
[...] « Low Power Methodology Manual Puzzle #10 - Mux Logic - Solution May 29, 2008 Puzzle #10 - Mux Logic, still didn’t get an official solution so here goes. If you are not familiar with the puzzle [...]