GPIO 0.3volts taking it HIGH?
I've got a strange problem with GPIO on an Omega2.
When I test my input through a digital test meter I see, at most, 0.3v coming from the equipment I am connected to. However the documentation for the Omega2 seems to say that you should only see a high input when it it goes above 2.0volts.
Any idea what is or could be going on?
When the connected equipment goes high (outputs 3.3volts) I see a constant HIGH on the Omega2 GPIO but it is slightly annoying seeing the LOW as as "flapping" between high and low.
I can only assume interference from mains wiring that runs alongside the twisted pair that I'm using to connect my equipment to the Omega2.
Any suggestions would be lovely.
It may be that your "low" is not actually driven, but just a floating line.
Or it may be that it has occasional high pulses on it, and the meter is only reading a crude (and perhaps very misleading) sort of sampled time average.
You could try a pull-down resistor to give an undriven line defined state, but it would be best to understand what the unspecified equipment is actually doing electrically - not just from an operational point of view but also the possibility of it doing something damagingly out of specification, or driving the line high when the Omega 2 is unpowered, which can also be problematic.
It is connected to a commercial gas boiler system. The terminals it connects to claim to just be a certainly doesn't output anything like AC or high DC when triggered. All the wiring does run directly alongside the main AC electricity feed into the boiler though.
I will see if I can borrow an analogue test meter and see if I can see it wobbling around.