I'm not at all experienced in these things, rather bumbling my way through it all.
I checked the figure of 6uA;- it's 2mA... and I may have misinterpreted the context too. From Steve Stallings at PMDX:-
"The inputs (pins 11, 12, 13, and 15) of the PMDX-122 need to be driven from a
circuit that can sink 2 milliamperes to ground with the voltage being driven within
0.4 volts of ground."
The code is all up to me.
I think I may be misunderstanding something quite fundamental here, maybe about microprocessors in general, or BoBs, or parallel ports:-
1) If my picaxe is normally outputting 5V INTO the input pin on the BoB, and then it goes low, does that then mean that the picaxe is driving the input pin to 0V? Or does it mean it's left floating? I assumed the latter, as I thought a lack of output from a microprocessor output pin just means it floats around, not tied to 0V.
2) Normally, inputs on my BoB are connected just to switches that act to ground the 5V that my multimeter tells me exists at the input pin. Having trouble getting my head around connecting inputs to anything other than switches; the idea of driving an external voltage into an input pin is a bit alien to me.
If I'm driving 5V into the input, is that input then just held at logic high (5V), or is it held at logic high with 5+5=10V potential? I baulked at the thought of trying that, it sounded like a way to ruin my BoB.
I'd be quite happy to connect the picaxe output (approx 15mA) to the input pin on the BoB and trigger Mach by sending it low; I'd like to understand what I'm doing a bit better before trying it. As I said, I'm probably missing a basic understanding of something here. Hopefully it's not too exasperating to attempt to explain it to me; the effort is certainly appreciated.