learning from mesa design :)

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14 Jan 2019 16:37 #124164 by arhi
I'm designing some new system and as I'm not that experienced I am looking for different ideas from other ppl's projects to try to compile something that will work for me. Checking out MESA cards I see a great setup with fpga talking serial to dspic and dspic then talking to port extenders to handle "slow" pins (like limit switches etc..) ... great idea, but I'm looking if I can "take" more from it, and since I don't own any of the daughterboards (I only have two 7i80hd board) I would like to know bit more about them (ordered few but looks like noone in europe have them on stock) .. major questions being
- is the firmware for the dspic open? (hex is available afaik)
- what are the io ic's dspic is talking to?

thanks :)

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14 Jan 2019 17:33 #124173 by PCW
Replied by PCW on topic learning from mesa design :)
Our DSPIC firmware is not open, chiefly because we don't want to have to
support users development efforts. All LinuxCNC related FPGA firmware is open however including firmware that implements sserial slaves:

freeby.mesanet.com/SSRE7IA0.ZIP

(This is for a new SSerial remote with 48 digitally filtered inputs 4 MPGs 24 Isolated outputs and 4 analog inputs, but the code is assembly and not terribly friendly)

You might also look at the open source STMBL motor drive project, it uses sserial as one interface method and is written in C.
The following user(s) said Thank You: tivoi

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15 Jan 2019 01:10 #124209 by arhi
Replied by arhi on topic learning from mesa design :)

PCW wrote: Our DSPIC firmware is not open, chiefly because we don't want to have to
support users development efforts.


:D I'm learning a lot from your fpga sources (I am still a total beginner, even "below" beginner) and from rest of your work so I have to use this chance to thank you for all that :)

PCW wrote: freeby.mesanet.com/SSRE7IA0.ZIP
(This is for a new SSerial remote with 48 digitally filtered inputs 4 MPGs 24 Isolated outputs and 4 analog inputs, but the code is assembly and not terribly friendly)

I'm familiar with x86 assembly (used to be very proficient, I doubt I manage to forget it :D it used to be my main source of income 30 years ago), never used it for pic but I hope I won't have issues understanding the code. Thanks.
Is the whole SSERIAL protocol documented somewhere or I should extract it from master and slave sw? Now that I have slave code and with fpga code should be simple but if there's a document that already exist would be cool :)

PCW wrote: You might also look at the open source STMBL motor drive project, it uses sserial as one interface method and is written in C.


this one?
github.com/rene-dev/stmbl
it's compatible with MESA cards I can add this to the end of 7i80HD-25 ?

now, for the second part of my question, 7i76, what are the driver chips dspic talks to? is it something like AM26C31 ( www.ti.com/lit/ds/symlink/am26c31-ep.pdf ) or ? by the size of the chips I assume it's something with more then 4 drivers in them? Also what's used for input? I assume dspic is not optically isolated from the drivers?

many many many thanks :) .. I figure all this will be way clearer when I finally get to get my hands on a 7i76(E) board but they are getting harder and harder to get in europe :(

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15 Jan 2019 02:06 #124215 by PCW
Replied by PCW on topic learning from mesa design :)
The output driver chips on a 7I76 (and others) are NCV7608 8 output ~ 350 mA relay drivers. These chips are is interfaced to the DSPIC over SPI The SPI is not isolated but the serial link to the DSPIC is isolated
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15 Jan 2019 02:22 #124217 by arhi
Replied by arhi on topic learning from mesa design :)
Thanks!

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