Connecting a single 7i76 to the P2 connector on 5i25

17 Mar 2017 16:52 #89829 by Simpson36
There are numerous configurations of 7i76 on 5i25, but all that I have found have the 7i76 connected to the P3 external connector. In this case, the DB25 is already being used, so I need to connect a single 7i76 to the P2 internal connector.

Can anyone point me in the right direction to learn how to do configure a single 7i76 on the 5i25's P2 connector properly?

17 Mar 2017 17:14 #89830 by PCW
The answer depends on what is connected to the DB25 connector
17 Mar 2017 18:50 #89833 by Simpson36
Thanks for the quick response.

This is for Tormach machines running Path Pilot. If it is important, I can get the exact pinout of the DB25, but it would be probably 4 stepgens and some I/O.

A little more detail: I can get the 7i76 working using the 7i76x2 firmware, but that still eats up 4 pins on the DB25 for the unneeded serial connection and those pins might be used, if not now, then in the future, by Tormach. I want to avoid the Tormach stuff as much as possible.

Specifically, what I would like to have is at least one step/dir for a servo and a couple of I/O pins to use on the 7i76 without changing anything on the existing DB25.
17 Mar 2017 19:33 #89834 by PCW
You cant really just guess about the P3 pinout (if you expect it to work with a Tormach breakout)

Probably the best thing would be to get the current pinout that works with Pathpilot
and add the 7I76 I/O to the second connector

The way to get the current pinout is this:

sudo mesaflash --device 5i25 --readhmid > pinout.txt

You may have to install a current copy of mesaflash on your system for this to work
17 Mar 2017 21:16 #89837 by Simpson36
Probably the best thing would be to get the current pinout that works with Pathpilot
and add the 7I76 I/O to the second connector

This is exactly what I need to do. I can find no examples or instructions on how to do it. There are examples and even step-by-step of how to connect a 7i76 to the DB25 on the 5i25, but so far, with a lot of searching, I did not turn up anything on connecting to the internal P2.

I have added configs from 'UPDATE5i25' (posted on the web) . I have the newest mesaflash and the newest pre-configs from the MESA site. It all works fine with PNCconfig, but there is no choice to put the 7i76 on the P2 connector.
17 Mar 2017 23:16 - 17 Mar 2017 23:16 #89838 by PCW
the first step is getting the current pinout:

sudo mesaflash --device 5i25 --readhmid > pinout.txt

Then a custom bit file is needed that puts a Tormach compatible pinout on P3 and a 7I76 compatible pinout on P2

(basically some cut/paste work on an existing pinout file and a re-compile)

BTW pncconf is not likely to help too much with a pathpilot config
Last Edit: 17 Mar 2017 23:16 by PCW.
The following user(s) said Thank You: Simpson36
18 Mar 2017 12:50 #89856 by Simpson36
pinout.txt attached.

"BTW pncconf is not likely to help too much with a pathpilot config"

Why is that?

On the P2 side, all I need is one stepgen (step/dir) and a couple of I/Opins

What is the next step in making the custom firmware?

Thanks very much for the help on this!
18 Mar 2017 22:52 #89870 by PCW
pncconf makes hal/ini files that a very different than pathpilots files

If you only need one stepgen and a couple I/O pins, the Tormach bitfile
should work fine as is with a standard inexpensive parallel port breakout board like:
19 Mar 2017 02:51 #89875 by Simpson36
I am aware that Path Pilot does things 'differently'. I have been digging into it again recently.

Perhaps I am missing something obvious, but I don't see where that break out board is going to be the solution.
There is already a cable plugged into the external DB25 on the 5i25 that is running the Tormach Mill. I cannot disturb that setup.

All I want is to add a 7i76 to a 5i25 on the P2 connector and so far I can find no existing .bit files that do this or examples of how to go about creating one. In another post on this forum, Big John T suggested to someone to "just add a 7i76 to the P2 connector" , so it would seem to be doable. That is what I want to do.

About a year and a half ago, I tapped into the P2 directy on a Tormach machine and rerouted the signals I wanted to that connector and it works fine. I just want to take that a step further and use the 7i76 because it has features that are useful, like using 24v signals. There is room to expand later with encoder readers and PWM and so on.

I mentioned that I have this working using the 7i76x2, but that assigns pins to the serial port on the 5i25 and I don't want to change anything on the Tormach side.

It seems odd to me that everything I can find on this topic always has a single 7i76 plugged into the DB25. Pncconf has no option for a single 7i76 on the P2 port. I'm not in love with PNCconf and I'm happy to edit the files direclty

One good thing is that your comment on custom bit files provided something different to search on and I came up with some documentation and examples on creating custom bit files. Hopefully, it will not prove as difficult as I am imagining it to be.

The search on custom bit files also turned up a couple of people who said that MESA had written custom bit files for their application, so that seems like another avenue to look at .

Thank you for the advice and suggestions.
19 Mar 2017 03:08 - 19 Mar 2017 03:09 #89876 by PCW
I suggested the simple breakout because you said you only needed 1 stepgen and a few I/O (a 7I76 is massive overkill for this)

The current Tormach config is compatible with adding simple parallel port breakout on P2 so that would give you
the desired I/O.

If you want to use a 7I76 on P2, and be compatible with the Tormach breakout on P3, a custom bitfile is required
Its not a big deal to make this bitfile but there is a possible stumbling block. I believe the Tormach config uses
a different encoder module that can use the index for counting and time based angle interpolation for the Rapidturn
I can probably duplicate this but I have not merged Tormach firmware code into my source tree so its a bit of a pain

If Rapidturn support is not needed I can easily whip up a Tormach/7I76 bitfile when i get a free moment if you like
Last Edit: 19 Mar 2017 03:09 by PCW.
The following user(s) said Thank You: Simpson36
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