7i95 + serial absolute encoder

Hi,

I have 7i95 in my retrofit project, which works fine for 3axes. Recently I added the 4+5th axis tilt/rotary unit and also I'd like to add encoder at least to the 4th axis to easily find zero position. I have Heidenhain ECN 113 encoders (a lot of) so it would be cost saving solution to use them. As they support 4 wire serial communication I considered to use the serial interface on 7i95 to connect them.
I have no experience in serial communication except Modbus, but AFAIK this is definitely not that.
I've tried to use sserial_port_0=0xxxxxx option in HAL file for hm2eth but I can't see any serial pin in the HAL configuration after load.
Do I need specific bitfile to use sserial interfaces, and it this "dream" even possible?
Thank you for your help!

Hostmot 2 supports 3 serial encoder formats:
Fanuc, SSI, and BISS, so to get the encoder to work
you would need to:

1. Determine if the encoder uses one of those formats
2. Use firmware that supports the actual encoder format

Hi PCW

thx for your fast reply, in my understanding this encoder supports SSI or BISS, manual is not so clear, I'd suppose I need try both
but which firmware shall I use, where can I obtain it please?

Thank you
Tamas

It would be best to figure out which interface your encoders
use rather than guess. Normally the full part number will
indicate what interface is used.

I don't think any standard 7I95 firmware supports SSI or BISS,
but it can be built easily, and use one or both of the built in
serial interfaces on the 7I95 card.

How can I build custom firmware, is there an up-to-date document?
Or can you make them if you have some free time please?
Thank you

There's this:
wiki.linuxcnc.org/cgi-bin/wiki.pl?Editing_MESA_Bitfiles

plus, I can make firmware if you know the interface type and where
you want to connect the encoders.