A blast from the past for PCW
10 May 2024 03:46 #300283
by PCW
Replied by PCW on topic A blast from the past for PCW
No, there is no SPI interface on the 8I20
There is access to the serial interface on the header
There is access to the serial interface on the header
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10 May 2024 04:03 #300286
by blazini36
Replied by blazini36 on topic A blast from the past for PCW
SPI interface coming off that PIC and some *special* firmware, I think it'd be a different beast....
.....just sayin lol
.....just sayin lol
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10 May 2024 12:12 #300312
by PCW
Replied by PCW on topic A blast from the past for PCW
SPI is not a great off board interface to line operated power devices...
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10 May 2024 13:07 #300320
by tommylight
Replied by tommylight on topic A blast from the past for PCW
+1SPI is not a great off board interface to line operated power devices...
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10 May 2024 23:47 #300360
by blazini36
It's a hypothetical question anyway since it doesn't actually exist but what problem couldn't be overcome with a little consideration on either side?
Kind of a moot point but the STMBL has an SPI header on it, for whatever that's worth.
Replied by blazini36 on topic A blast from the past for PCW
What's the concern using SPI in a board to board configuration on something like an 8i20 that's powered off a DC bus of the user's making? the 8i20 isn't really scared of isolators so I'll get the obvious out of the way and I assume that motor driver doesn't spray too much EMI all over the transmission lines cuz it looks like a PIC sits right on top of it.SPI is not a great off board interface to line operated power devices...
It's a hypothetical question anyway since it doesn't actually exist but what problem couldn't be overcome with a little consideration on either side?
Kind of a moot point but the STMBL has an SPI header on it, for whatever that's worth.
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11 May 2024 00:08 - 11 May 2024 00:14 #300362
by PCW
Replied by PCW on topic A blast from the past for PCW
On card with a ground plane SPI is fine. Between cards in a motor drive
with volts of ground bumping and clock signals that are susceptible to 10 ns
spikes would likely require isolation. Isolation is a bit fussy for SPI because it needs
3 or 4 pins and skew is important (a good reason to use serial instead)
Its certainly possible but unless you had a good reason to do it, its probably not
worth the trouble.
with volts of ground bumping and clock signals that are susceptible to 10 ns
spikes would likely require isolation. Isolation is a bit fussy for SPI because it needs
3 or 4 pins and skew is important (a good reason to use serial instead)
Its certainly possible but unless you had a good reason to do it, its probably not
worth the trouble.
Last edit: 11 May 2024 00:14 by PCW.
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11 May 2024 00:41 #300364
by blazini36
Now that I think about it SPI wouldn't do any good anyway. I doubt you could have that PIC do the things it's currently doing and be the EtherCAT application processor as well. ESC would likely have to connect to a dedicated MCU on that PCB then yeah maybe that MCU could just interface the 8i20's PIC over serial.
I haven't put a ton of thought into it, I just saw my 8i20 and said "wow that's a cool idea". Does the current serial protocol/ firmware etc facilitate the purpose of the Unicorn board that may or may not have turned it into a velocity mode drive?
Replied by blazini36 on topic A blast from the past for PCW
EtherCAT!!!!On card with a ground plane SPI is fine. Between cards in a motor drive
with volts of ground bumping and clock signals that are susceptible to 10 ns
spikes would likely require isolation. Isolation is a bit fussy for SPI because it needs
3 or 4 pins and skew is important (a good reason to use serial instead)
Its certainly possible but unless you had a good reason to do it, its probably not
worth the trouble.
Now that I think about it SPI wouldn't do any good anyway. I doubt you could have that PIC do the things it's currently doing and be the EtherCAT application processor as well. ESC would likely have to connect to a dedicated MCU on that PCB then yeah maybe that MCU could just interface the 8i20's PIC over serial.
I haven't put a ton of thought into it, I just saw my 8i20 and said "wow that's a cool idea". Does the current serial protocol/ firmware etc facilitate the purpose of the Unicorn board that may or may not have turned it into a velocity mode drive?
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11 May 2024 01:29 - 11 May 2024 01:41 #300365
by PCW
Replied by PCW on topic A blast from the past for PCW
Ethernet/Ethercat does not have sufficient isolation for line powered devices
so the original 8I20 architecture with serial interface to a torque mode drive
does make some sense.
Another way is to use isolated gate drivers and say a AMC130M02 for current sensing...
so the original 8I20 architecture with serial interface to a torque mode drive
does make some sense.
Another way is to use isolated gate drivers and say a AMC130M02 for current sensing...
Last edit: 11 May 2024 01:41 by PCW.
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11 May 2024 02:17 #300367
by blazini36
Replied by blazini36 on topic A blast from the past for PCW
is the serial pin header on the 8i20 isolated? Which header is it, the one on the right side of the PCB i assume?
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