how to optimize a MUX with 256 input pins to reduce area?

[mark_alin]

how to optimize a MUX with 256 input pins to reduce area? I find that the area of the MUX is too large.

thanks a lot!

 

[bg21359]

Re: how to optimize a MUX with 256 input pins to reduce area

Maybe you can do 8:1 mux (total 32), then 8:1 mux(total 4), then 4:1 mux.
So total you need 36 8:1 mux and 1 4:1 mux

 

[papertiger]

Re: how to optimize a MUX with 256 input pins to reduce area

feed it into DC, I think the DC will give you a better result.
Mux may be to big for area, but it may be the least wire routing.

 

[soccer]

using dc to solve your problem. or other asic synthesis tools.

 

[amaccormack]

Re: how to optimize a MUX with 256 input pins to reduce area

If your synthesis tool cant improve the area much (make sure its optimizing for area, not time) then you may have other options, depending on what you are muxing. For example, making the outputs of the 256 things that you are muxing be =0 when not in use, then just ORing the outputs together. Or tristates, if your DFT methodology allows it (probably not a good idea). Or, can you rearrange these 256 things into a shift register structure. Or, if they are just memory elements, how about using a RAM instance?