Multiplexing digital inputs

Forum 2005-2010 (read only) Hardware Interfacing
1

I'm working on a project that involves measuring the frequency of a 555 timer by connecting the timer output to one of the Arduino interrupts and counting the rising edge of the pulses.

I have this working but the next step is to expand this to be able to poll multiple timer chips. I probably only need to poll each timer every couple of minutes and the frequencies are in the kHz range so I think this should be easy.

I think I could do this with a 4051 multiplexer but I know this chip is designed for switching analog inputs. Since I have a TTL level input is there a digital equivalent which would be better for this job or should I just try the 4051?

Thanks in advance.

2

For TTL digital multiplexers, try the 74HC151 or 74HC153. I think the 151 is a single 8-way and the 153 is a dual 4-way. Send two or three bits of input selection code, then read the digital input for that selected 555's pulses.

3

That is perfect, thank you.

Now that I know the chip name I found this article in the playground.

http://www.arduino.cc/playground/Code/MUX151

I missed it the first time and only saw the information about the 4051.