On Fri, 9 Apr 2021, John Dammeyer wrote:
Date: Fri, 9 Apr 2021 10:34:30 -0700
From: John Dammeyer <jo...@autoartisans.com>
Reply-To: "Enhanced Machine Controller (EMC)"
<emc-users@lists.sourceforge.net>
To: "'Enhanced Machine Controller (EMC)'" <emc-users@lists.sourceforge.net>
Subject: Re: [Emc-users] Small PC for use with 7i90 / 7i96?
From: andy pugh [mailto:bodge...@gmail.com]
On Fri, 9 Apr 2021 at 17:40, John Dammeyer <jo...@autoartisans.com> wrote:
> Your photo of the 7I80 is clearer than the one on the MESA site. But I can't
figure out what the difference is between the 7I80DB-16
and -25. Which one do you have and why?
It's a "16" as it has a 16 k-gate Startan 6 FPGA. The "25" has 25 k-gates.
You can fit a bigger, more complicated, firmware on the 25k one. I am
not sure if any 7i80 firmwares need the 25kgates.
I have the one that I have because that's the one PCW gave me as a
development sample ;-)
Ah! Now that makes sense. Possibly the larger could be used to allow a
non-firmware reprogramming to allow step/dir _or_ pwm/dir on the same two pins.
Right now my MESA 7I92H can't do that while an Ethernet Smooth Stepper with
MACH can.
But that's an apples and oranges comparison from what I understand because of
what happens inside the FPGA on both.
John
You could do this in hal either by using the stepgen as a PDM generator
(assuming the PWM is just filtered to obtain a analog voltage)
or disabling the stepgen and using software PWM (low PWM frequency only)
The issue is not FPGA resources, but rather the overall architecture differences
Besides you could simply re-write the firmware for each machine automatically
(it would take a while to wear out the 100K write cycle life flash chip even if
done 10 times a day or so)
--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
?? George Fitch, Atlanta Constitution Newspaper, 1912
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Mesa Electronics
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