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How do I use a multiplexer? Answered

I have a bunch of assorted multiplexer chips I purchased in a grab bag a while back. I want to get my self familiar with them at the most basic level. I understand what multiplexing is by definition only, but not enough to really understand how to use one. 

How would I go about testing out the pins for example, or is it even possible to use just 1 multiplexer IC with a 555 ic for the clock to understand what is going on?


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Best Answer 8 years ago

No don't ever supply IC numbers it would confuse us.

If you multiplex signals or data on one end of a twisted pair,
then you must de-multiplex on the far end.

A simple scheme is to run a twisted data pair and another 2,3or 4 wires
for address.
2 wires gives 4 addresses
3 wires gives 8 addresses
4 wires gives 16 addresses
On the mux you select an addr and send data
until you change the addr and send more date, etc, etc.

Some schemes avoid the address wires by including a header
in every new data file indicating destination address but that is
the internet :-)



8 years ago

Be nice you two ;)

I didn't have the chips handy when I posted this, and I read the data sheets; but I honestly find them a little confusing.

1 of the chips I have is 74157 which is a mux based on what the DATA SHEET tells me and another one I have is 74153 which is a de-mux.

As I stated, I am not really clear on how to use/experiment with them.

Iceng; what you said kinda makes sense. When you say to run a twisted data pair I assume you mean run them to the selector pins?


Answer 8 years ago

You can think of the 157 as a Four_Pole Three_Way switch.

Two of them could be used to switch between two eight bit buses.