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Question about galvanic isolation #4

Closed InterFelix closed 3 years ago

InterFelix commented 3 years ago

I'm working on an updated version of this using a CAN-Controller-Transceiver combination chip (MCP25625 to be exact) in a RasPi-HAT form factor. I looked at your galvanic isolation section and could not really understand why you set the power supply portion up as you did. In particular, I do not understand why you use mixed voltages for the optocouple inputs/outputs, and why you use the S88 5V for the S88-Data-optocouple-Input, particularly (but then use the 3.3V Rail from the Raspberry for the S88-Data-Output). On all the other lines it seems like a proper galvanic isolation, but on the data rail it seems oddly switched. Can you explain your thoughts behind the design to me, so I can build on your experience? I'm really not an electrical engineer or know much about this type of stuff, just enough to find my way around, but that's about it.

InterFelix commented 3 years ago

Found out myself thanks to @GBert 's post in #2