Kubs wrote: ↑Sun Nov 22, 2020 7:52 am
I did not tie together the ground of teensy and pi together as it is allegedly irrelevant for the bus working - as I found only the transmission speed may vary.
Thats a common mistake (pun intended!), the signals must be within the common-mode range so the 0V should be tied together.
Laptops can be great for blowing up CANBus chips, thats why the standard 'OBD2' socket has protuding 0V connections - to equalise the grounds before the signal lines make contact.
You can't loop the CANBus back like a UART but some CAN chips do have a loopback capability that can be enable in software, check the datasheet.