- With the g540 disconnected, verified that port 1 pin 3 does not change voltage regardless of the axis move direction. Pins 5 and 7 behave as expected.
- Complained to CNCDrive that my UC400ETH might be bad. Got reply that they're 100% tested, and maybe it's a configuration issue.
- Found a thread here about a similar problem caused by two functions on the same pin. I manually checked for that problem, and used the pin mapping plugin to verify that there's no extra function mapped to pin 3.
- Moved X, Y, Z, and spindle to port 2. I get the exact same behavior. That should rule out a hardware problem, I think.
- Verified that the UCCNC software thinks that pin 3 is in the correct state. It shows it high when it should be, and low when it should be.
Through all of this, the actual voltage on pin 3, on either port 1 or port 2, stays stubbornly at 0.0V
Where else can I look? This limits the parts that I can make