5i25 7i85S

I have a Mesa 5i25 and 7i78, and with some help from this forum I've managed to get them set up and working. I would like to add a 7i85S, mainly for adding encoders to monitor position on x and z of a lathe. My understanding is I need to update the 5i25 firmware for the new board to be used. I've found a config at Mesanet.com to do the 5i25/7i85S/&7i78 combination. Is it just a case of buying a 7i85S, updating the 5i25 firmware, and connecting to the 2nd port of the 5i25 ?.Out of interest, do the components, (stepgen, encoder etc) all run on the 5i25 ?.

Thanks, John.

Yes it is as simple as downloading the files and re-flashing your 5i25. It will matter which port the 7i78 and 7i85S is plugged into. (You might have to change the port that your using your 7i78 on.)

Yes the 5i25 is doing all the "work" with the step generation and encoder counting. The daughter cards are the "interface" but do things like converting differential signals to what the 5i25 can use, or in the case of the encoders break out the muxed signals.from 4 encoders to a smaller number of inputs. on the 5i25.

Thanks Todd. These lines form the Linuxcnc manual can give the impression something has to be downloaded to the breakout boards,' hostmot2 is a device driver that interfaces the Mesa HostMot2 firmware to the EMC2 HAL. This driver by itself does nothing, the boards that actually run the firmware require their own drivers before anything can happen.'
I will order a Mesa 7i85S etc and re-flash the 5i25. I'll check on the order of the 7i78/7i85S as you suggest.

When you order your 7i85S ask Mesa for instructions for doing what you want to do. They should be able to give you detailed instructions including links to the the files you need to download.

I've ordered a 7i85s, and flashed 5i25_7i85s_7i78.bit file to my 5i25. I've connected my 7i78 to P2 on the 5i25,(the 7i85s has not arrived yet). I cannot get any input from my encoder with this setup. 5i25_7i85s_7i78.pin shows three encoders, the third being on the 7i78, but nothing shows up on show hal configuration. The step/dir output works ok. If I flash 5i25_7i78x2.bit file to my 5i25, the encoder works as normal (setting up as second encoder) with the 7i78 on P2.
I would also like to use the spare step/dir connections on the 7i78 as inputs, but am not sure if this is possible with the 7i78 on P2.
I would be grateful for some advice on this.

I've made a bit of progress. The 5i25_7i85s_7i78.bit file appears to create 6 encoders in total. With the 7i78 in P2, and installing all 6 encoders, (loadrt hm2_pci config="num_encoders=6 num_pwmgens=0 num_stepgens=5 sserial_port_0=0xxxxx"), the last encoder input is working. This is very confusing, as 5i25_7i85s_7i78.pin, shows only three encoders. I guess its just down to the flexiblity of linuxcnc.
I'd still like to know if the spare step/dir outputs on the 7i78 will be available as gpio.

0nly 3 encoders are shown in the FPGA pinout because the 7I85S uses multiplexed encoder inputs to save pins
so each encoder pin on the FPGA interface provide the signals for 2 encoder counters, that is, for example,
the Channel 0 QAUD-A pin provides the A signal for encoder counters 0 and 1.

7I78 outputs not used at stepgens can be use as TTL level outputs, and spare encoder inputs can be used
for TTL level digital inputs.

Thanks for the explanation PCW. This combination leaves me a bit short of inputs, as I will use quad encoders on x, z and spindle for a lathe. I guess that only leaves the spare encoder inputs on the 7i78. This is ok as I have a couple of parallel ports, which will give me a total of 13 inputs.

If you only use 3 encoder inputs (X,Z,Spindle) you should have 2 encoders free (one on 7I85 and one on 7I78) so 6 inputs
Note that you could also use unused index inputs (so if X and Z dont home to index, the index inputs are free)

Thanks for the update, that will give me plenty of inputs. you mentioned "7I78 outputs not used at stepgens can be use as TTL level outputs". I tried to drive the spare one's as gpio outputs on the 7i78, but although they appeared available on show hal configuration, and could be forced to on there, there was no output on the 7i78. This was using the 7i85s/7i78 firmware.