[arm-allstar] HamVoIP I/O support - What is Best Current Practice for implementing I/O?

[Randy Neals]

Hi,

What is the best current practice for implementing I/O on a Raspberry Pi to
control external things.
In this case, remote channel selection on a VHF remote base, a radio with 8
channels and having external control lines.

>From looking through the list archives, I see references to using an
Arduino Nano, and at an earlier time, using a USB I/O board from SparkFun,
and of course using the lines on the RPi itself.

Anticipated questions...

Q. What Am I trying To Do?
A. Control channel select lines on a VHF remote base station.

Q. What format/How many lines?
A. 3 logic control lines. The lines are normally pulled up to +5V by the
radio.
     BCD format with the lines having binary weighting of 4, 2, and 1
respectively.
     High = weighted value / Low = zero value.

Q. What audio interface will I use?
A. Simple USB, likely DMK URI. (But I could use a USB FOB, or other
interface if there is one with I/O)

Thanks,
Randy
W3RWN