Help muxing devices

[Razzel]

I am a bit of a hack at this and need some help if anyone has experience
with attaching devices to the parallel (aka printer) port.

I have 3 devices which I would like to read in a round robin approach.
My current program just reads 1 device, changing it to read 3 is a snap.

It reads the serial info off of pin 6 of an ADC0831 via pin 12 on the
RS232. The other pins used are 1, 3 (optional) and 4 of the ADC.

My reasoning was ;^) to connect all the ADCs in parallel except pin 6
which I was going to connect to one of the switched in a CD4053 mux
input and connect their outputs together to pin 12 of the RS232.

Then I realized I might be messing up my parallel port with more than 1
chip.

1) will the parallel port be overloaded with this scheme?
2) will there be enough oomph to carry the signals to all 3 of the ADCs?

If you have experience using the SB sound line in can you tell me if a 3
v zener is enough to protect the board if a signal should go to say 4-5
volts?

Thanks for your input,
Ron

 

[loedown]

Keep in mind that ADC have a settling time and you cannot exceed that,
otherwise the summing circuit will not give you an accurate sample, that
will limit your mux circuit

Paul