mesa 7i76E - new pinout?

PCW wrote: You can imagine its impossible to have bitfiles for every daughterboard combination
so odd combinations are very likely to require custom bit files

Sure! You can't anticipate any required combination.

The question is: what, if someone wants a weird combination?
Are you willing to help create a custom bitfile?
That bitfile could then be archived and documented, so if other come with similar requirements, an appropriate bitfile will already be there.
For me, the requirements from xilinx are absolutely ridiculous, so I don't rip of my cloths to download an outdated piece of software, which overwhelms my harddisk just for single shot usage.

So what about a service for custom bitfiles?
I'm willing to pay for a custom bitfile, if that bitfile will be published to community, the same way as all other bitfiles.
Well, the price for a bitfile should not exceed the board price

My wish for extension slot / 7i85S would look like:

so if I did not make a mistake, all encoders could be connected to linuxcnc

... and of cause, I'm willing to document the bitfile ...
by the way: the whole bunch of ethernet mesa cards is missing in linuxcnc manual

Reinhard wrote: My wish for extension slot / 7i85S would look like:

Are you sure that that matches the 7i85S hardware?

The 7i85S uses muxed encoders (2 encoders share FPGA pins). This it built in to the 7i85S hardware.
Also, the 7i85S pin directions are set by hardware.

The bitfile mentioned earlier, which already exists, is set up to put all the right pins in the right places for a 7i85S to connect 5 stepgens and 4 encoders to the 7i76E.

andypugh wrote:

Reinhard wrote: My wish for extension slot / 7i85S would look like:

Are you sure that that matches the 7i85S hardware?

I'm sure, that I'm not sure about anything
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andypugh wrote: The 7i85S uses muxed encoders (2 encoders share FPGA pins). This it built in to the 7i85S hardware.

Oh, that does not sound good. Muxed pins means, less speed - right?
So may be another daughter board will be more appropriate?
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andypugh wrote: Also, the 7i85S pin directions are set by hardware.

OK, that's reasonable.
Depending on whether a pin is routed to a transmitter or a receiver?
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andypugh wrote: The bitfile mentioned earlier, which already exists, is set up to put all the right pins in the right places for a 7i85S to connect 5 stepgens and 4 encoders to the 7i76E.

Hm, but if the pin-setting was lost, the bitfile is of little use - isn't it?

So if the restrictions arise from the 7i85S - is it possible to realize that pin-settings for the 7i76E so that I can build my own daughterboard that offers the functionality I'd like to get?

Reinhard wrote: Oh, that does not sound good. Muxed pins means, less speed - right?

Not to any meaningful extent. (Maybe even not at all). Lots of Mesa cards use muxed encoders to save on IO pins.

andypugh wrote: Also, the 7i85S pin directions are set by hardware.

OK, that's reasonable.
Depending on whether a pin is routed to a transmitter or a receiver?

Exactly.

Hm, but if the pin-setting was lost, the bitfile is of little use - isn't it?

I don't understand the question. The bitfile is what defines the pin functions.

So if the restrictions arise from the 7i85S - is it possible to realize that pin-settings for the 7i76E so that I can build my own daughterboard that offers the functionality I'd like to get?

Yes, but you would need a custom bitfiile, and as far as I can tell the existing bitfile and the existing 7i85S give you the functions that you are wanting. How many encoders do you actually need? Don't forget that there is one on the 7i76E + 2 x MPG and 4x MPG on the 7i73.

I made my own breakout for the 7i43 using the ULN2803 for output and optos for input. But I only did it once.

andypugh wrote:

Reinhard wrote: Oh, that does not sound good. Muxed pins means, less speed - right?

Not to any meaningful extent. (Maybe even not at all). Lots of Mesa cards use muxed encoders to save on IO pins.

Ok, so may be I don't understand muxing with FPGA
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andypugh wrote:

So if the restrictions arise from the 7i85S - is it possible to realize that pin-settings for the 7i76E so that I can build my own daughterboard that offers the functionality I'd like to get?

Yes, but you would need a custom bitfiile, and as far as I can tell the existing bitfile and the existing 7i85S give you the functions that you are wanting. How many encoders do you actually need?

Well, I'm stil thinking about your advice, bringing the encoders to linuxcnc.
And I thought, the 7i85S is just a single line to differential line transcoder.
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andypugh wrote: Don't forget that there is one on the 7i76E + 2 x MPG and 4x MPG on the 7i73.

Never mind, I don't bother with MPG lines. Guess the 7i73 will suffice for my requirements.
No - the encoder lines from 7i85S are the stepper encoders - therefore I hesitated about speed.
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andypugh wrote: I made my own breakout for the 7i43 using the ULN2803 for output and optos for input. But I only did it once.

Well, I will do a breakoutboard only once too. Hopefully
I got the hint, that a max490 will be a decent transmitter

What about this pin-setting for a 7i85S - is it manageable?