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Unable to send data to Teensy #80

Closed lansalot closed 11 months ago

lansalot commented 11 months ago

Evening all

Am playing with using SavvyCAN to send to Teensy 4.1 on an agOpenGPS board - the board works fine speaking to the machinery, no issues, but on the bench, if I go direct through the same cabling and send data with SavvyCAN, the teensy never hears about it for some reason. Full trace playback, nothing on Teensy.

Same baud rate, all good - so I was wondering if perhaps it's bus-related, and termination, so I tried with terminating on the meatpi, but no difference. I did notice if I check voltage on CANH/CANL on meatpi, they're actually back to front and L is higher than H.

All CANBUS wiring on the board is good, as it speaks to machinery with no problem. Am I missing something with the meatpi, some settings perhaps, or maybe a tweak with SavvyCAN?

Should I be standing up like a fake CANBUS on a breadboard, with terminators there perhaps, and wiring both into it?

(Appreciate this is quite probably not a meatpi issue, but I figure you guys will know the score here)

lansalot commented 11 months ago

Annnd, in case anyone ever comes up against this, this just won't work with the Teensy and Meatpi wired together. You need to have a proper CANBUS, so a breadboard with two 120ohm resistors at each end and we're all good !