MESA 5i25 + 7i85S

Yes GPIOs 0..7 (P3) or 17..24 (P2) are stepgens in normal 7I78 configs

I will add the host connector pinout of the
7I78 to the manual when I get a chance.

PCW wrote: Yes GPIOs 0..7 (P3) or 17..24 (P2) are stepgens in normal 7I78 configs

I will add the host connector pinout of the
7I78 to the manual when I get a chance.

Thanks Peter, that will help.

I have been able to use some of the GPIOs as output, but have not succeeded in making an input, yet.

I have another tactic: I will try a set of pins that I have successfully used as outputs and try to use them as inputs. That way I know I have the correct pins.

-Larry

If you are using 2 daughtercards, GPIO is basically unavailable except in a very restricted way
that is the step/dir pins are buffered so can only be outputs, with a 7I85S and a 7I78 there
are really only a few possible input pins (encoder inputs on the 7I78 are really all that are usable
the sserial input could be used but its differential and terminated so awkward

Peter-

OK, that's the problem. I thought I could use all the unused 7i78 StepGens as GPIOs either input or output.

I had succeeded in using the SSerial input on the 7i85S as a GPIO input. I will give the encoder inputs on the 7i78 a try as GPIO inputs.

I can rearrange my wiring, now that I understand what is expected.

I would like to use the PWM module of the 7i78 to run my VFD. Is the isolated potentiometer output on the 7i78 suitable for connection directly to the potentiometer inputs on a VFD?

Thanks,
Larry

Yes that is its intended use (as long as minimum and maximum voltage ratting are obeyed)

PCW wrote: Yes that is its intended use (as long as minimum and maximum voltage ratting are obeyed)

I will find out in a few hours if the "magic smoke" comes out of any of the components when I hook up the VFD!

The only question remaining is why Pncconf starts the IO pin numbering on the P2 connector at 24 instead of 17. Like you said, Pncconf 'should' use the "portwidth" parameter of 17 in the xml file. Hopefully Chris will see this and comment.

Thank you for your help, without a lot more documentation and time I would not be able to figure this out.

-Larry