Mesa 7i92TM+7i77+7i76U configuration

I currently have a machine that uses a combination of a Mesa 7i92TM and 7i77. But all axis outputs are used and I need another axis for a toolchanger. I want to use a 7i76U for step/dir controlling a servo. Can I use the 7i92t_7i77_7i76d.bin for this or is the 7i76U a different board? If I need an other .bin file, can someone make it for me?

7i92t_7i77_7i76d.bin is fine for a 7I92T + 7I77 / 7I76U setup.

The only case where 7I76U specific FPGA firmware is needed
is when you want to use the  7I76U's serial port in RS-485 mode
(say for Modbus), but even if you need Modbus, you could use the
7I77s serial port (that natively supports RS-485)  for that.
 

Okay, thanks! Is the .bin file for 7i77 the same as for 7i77U?

Yes, the 7I77U is identical to the 7I77 and 7I77D  FPGA interface wise.