7i76e - can unused axis stepgen be used for GPIO?

I have a 7i76e I am using for a lathe project and unfortunately, I need both 24VDC outputs for driving relays and 5VDC inputs for the factory opto switches.

I am only using 3 of the available axis step generators on TB2 & TB3. Can some of these be configured as TTL type inputs (0 or 5VDC)? If so, can you please give me an example of the HAL lines used?

Sorry, for my ignorance. I'm new to Linux and Linuxcnc and it's a bit of a learning curve.

I don't know alot about the 7i76e (I don't think many do). Hopefully Peter will chime in with the best solutions.

There may be several ways to do this. I think some of the field io can be used to sense a mix of either 5v or 24v input sources. I know this is the case when some of them are used for an MPG input.

An other way might possibly be using one of the expansion slots as TTL GPIO, perhaps with a 7i75 added for protection.

The step/dir pins are output only.

As Todd mentioned, the easiest way to add 5V IO is to use one of the expansion connectors and
either a 7I75 or a generic parallel port Breakout card.

The expansion port pins can be used directly for 5V signals but a connection mistake will be costly...

deoes anybody know how to invert the dir output in the step gen of mesa 7i76e

Typically you don't need to, you just chose the other output
if single ended or swap the + and - output if the driver is differential

grijalvap wrote:

deoes anybody know how to invert the dir output in the step gen of mesa 7i76e

As Peter says, I simply swapped the A+/A- wiring on the stepper controller with B+/B-