7i96 P1 Expansion

Is it possible to add an MPG to 7i96 through the P1 expansion connector 
 

You can add a MPG counter on P1 but note that you have to be
careful to not connect any pin on P1 to a voltage outside the 0 to 5V
range or to frame GND (which often has a volt or two of HF AC noise
so can drive excess current into the P1 pins when negative) This will
damage the BUS switch or the FPGA.

Here is a configuration that includes 4 MPG encoder inputs on the first
8 pins of P1 (26 pin header pins 1,2,3,4,5,6,7,8):



 

I actually managed to get this working last year. A lot of reading others posts and google but I got there in the end. I did communicate with someone outside the LCNC community about various aspects of his solution. He was using the same type of jog pendant as I bought online and you can find his description on his website wapl.es/cnc/2020/02/23/linuxcnc-jog-wheel-setup.html. The problem with these generic Chinese pendants is that the wiring is not always identical so a bit of work with the multimeter is required. I've attached my finished mpg.hal file which should be referenced in the INI file.

 

With reference to PCW's answer, I was intrigued as to his solution as he is from Mesa but although recognising the .bit file (but unreadable for me), I hadn't seen that example in the 7i96.zip file I downloaded from Mesa, I used the 7i96_5abob_d (pin file is readable). The other vhd file is also an unknown to me apart from the fact that it belongs with the included source files.

I recently installed inductive limit switches (NPN NC) which physically seem to work well with the 7i96 but I'm having some trouble with "joint # on limit switch errors" on all three joints when turning it on in the GUI. Must be something in the config and I might have to ask for help in the forum myself.

The advantage of the bitfile I provided is that it can use 1X mode on
the MPG encoders which is better for 100 PPR MPGs with detents
as you get 1 increment per detent.