encoder or mux?

Question

I have 8 switches but only 5 inputs to my microcontroler, so the idea was to encode( switch 1 is 0001, switch 2 is 0010......ect ). I need to keep power consumption down so I was told not to use a 74148 encoder but to use a 4067 line mux, but this doesn't help me. Is there another solution, maybe a low power encoder?

Answer 1

You should use an encoder, but to save power do not use a 74-series TTL. You should be able to find a CMOS equivalent in the 40-series or 74C-series. Have you looked for a 74C148?. The advantage of an encoder is that it is passive; the microcontoller just reads the value. For a mux, the contoller must output a signal to select which switch is to be read.

Answer 2

Why don't you want to use a line mux?

Use your microcontroller to control the address lines to the mux and read the output, you can then read the state of any switch you want and only use a single input to your microcontroller. You'll only be using 1/2 the mux as well.

Answer 3

In your case, you will need encoder not multiplexer.CMOS version of 74148 can be used for low power consumption.See the link below.Hope this will help.