7i96 bit files

The 7i96.zip file contains 20 different .bit files. Is there something that explains what each one is for? I want one with a packet UART so I can implement the RS485 transceiver IF. There's one called 7i96_pktd.bit which might be it. My fear is that I'll brick the card if I program it wrong. If I do choose the wrong bitfile, how do I restore it with the original one? Thanks.
Jim

The .bit files have an associated .pin file which is a text file
giving the configuration modules and pinout.

7i96d.bit is the standard bitfile

7i96_pktd.bit is the 7I96 configuration with a packet UART
Though I think the pinout file was made before Mesaflash
knew what a PKTUART was.

The current mesaflash does print out 7i96_pktd pinout correctly:

IO Connections for TB1/TB2 -> 7I96_1
Pin#                  I/O   Pri. func    Sec. func        Chan     Sec. Pin func   Sec. Pin Dir

TB1-2,3                17   IOPort       StepGen          0        Step/Table1     (Out)
TB1-4,5                18   IOPort       StepGen          0        Dir/Table2      (Out)
TB1-8,9                19   IOPort       StepGen          1        Step/Table1     (Out)
TB1-10,11              20   IOPort       StepGen          1        Dir/Table2      (Out)
TB1-14,15              21   IOPort       StepGen          2        Step/Table1     (Out)
TB1-16,17              22   IOPort       StepGen          2        Dir/Table2      (Out)
TB1-20,21              23   IOPort       StepGen          3        Step/Table1     (Out)
TB1-22,23              24   IOPort       StepGen          3        Dir/Table2      (Out)
TB2-2,3                25   IOPort       StepGen          4        Step/Table1     (Out)
TB2-4,5                26   IOPort       StepGen          4        Dir/Table2      (Out)
TB2-7,8                27   IOPort       QCount           0        Quad-A          (In)
TB2-10,11              28   IOPort       QCount           0        Quad-B          (In)
TB2-13,14              29   IOPort       QCount           0        Quad-IDX        (In)
TB2-16,17              30   IOPort       PktUARTRX        0        RXData          (In)
TB2-18,19              31   IOPort       PktUARTTX        0        TXData          (Out)
Internal-TXEn          32   IOPort       PktUARTTX        0        TXEna           (Out)
Internal               33   IOPort       SSR              0        AC Ref          (Out)


 

Oops ,found a bug in the distribution bitfile (LinuxCNC will complain about it)

Here is a fixed 7i96_pktd bitfile