7i96 firmware descriptions?

I'm trying to figure out if it's possible to use my 7i96 to send data over rs485 to my vfd. (seems like the answer is yes but I need to do a fair bit of work to do so)

From the research I've done it seems like there's a firmware available (7i96_pktd.bit) that exposes a serial interface on TB2 pins 16-19

I'm just wondering if there is any sort of documentation on the various firmwares available for the 7i96...

For the specific configuration,

mesaflash --device 7i96 --addr ip_add --readhmid

Gives you the pinout and firmware module content of a specific bitfile

For low level register description of the module interfaces there
is the regmap file included with the VHDL source