Following on from Pt.1...

Before starting to experiment too much with the logic analyzer, I decided to try and check what was going on with the 4 outputs using the analog pins of an Arduino Uno I had laying around. I already knew the voltages were 5V so connecting the outputs directly should be safe.

I wrote a quick & dirty script that simply read the value from each analogue pin I had connected in turn, converting the reading to a voltage and printing  it via a serial connection. Really simple.

The results? Not much to see...

0.05,5.00,5.00,0.42
0.00,5.00,5.00,0.66
0.01,5.00,5.00,1.26
0.00,5.00,5.00,1.64
0.00,5.00,5.00,2.19
0.00,5.00,5.00,5.00
0.00,5.00,5.00,5.00
0.00,5.00,5.00,5.00
0.00,5.00,5.00,5.00
0.00,5.00,5.00,5.00
0.00,5.00,5.00,5.00
0.00,5.00,4.97,5.00
0.00,5.00,5.00,5.00
0.00,5.00,5.00,4.94
0.00,4.98,5.00,4.33
0.00,5.00,5.00,3.45
0.00,5.00,5.00,2.75
0.00,5.00,5.00,2.04
0.00,5.00,5.00,0.00
0.00,5.00,5.00,0.00
0.01,5.00,5.00,0.00
0.00,5.00,5.00,0.00
0.00,5.00,5.00,0.00
0.00,5.00,5.00,0.19
0.00,5.00,5.00,0.15
0.05,5.00,5.00,0.28
0.08,5.00,5.00,0.42
0.00,5.00,5.00,0.86

Looking at this, it appears the first output is a ground value. The last one has some variation on it, but the remaining 2 are held at 5V.

At least I now know which output to connect to the GND for the logic analyzer ;-)