A few questions:
- is enabling CAN_PWR required to use the 3 basic IO pins on the external M8 connector?
- are the schematic and gerbers for the Tracker One PCB on github up to date with the Tracker One that’s shipping?
I’ve been fighting trying to get digital IO working on the Tracker One’s M8 connector for a while, and after a few days of debugging it seems like I can only output on D8/D9/D3 if I’ve also enabled CAN_PWR. Is that expected, and if so, is it documented anywhere?
Without CAN_PWR enabled I only see a few millivolts on those IO pins, rather than 3.3V, when setting any of those pins HIGH. I stumbled upon the fact that enabling CAN_PWR seems to allow them to work as expected, but I don’t think I’ve seen that documented anywhere, and ideally I’d like to use the IO without having to power the CAN transceiver and 5V boost converter. This also does not match the behavior of the Eval board, where those pins seem to work fine without having to enable CAN_PWR.
Would it be possible to update the schematic and gerbers at tracker-hardware/eagle-carrier at master · particle-iot/tracker-hardware · GitHub with the latest version? As far as I can tell those are an older revision, which added to my confusion when debugging; on that schematic those 3 IO pins go directly from the SoM to the JST connector, with a simple TVS diode to ground, so I initially couldn’t figure out any plausible reason that the outputs wouldn’t work.
Looking more closely at the board/schematic, I don’t see the 16-pin chip (labeled something like ZUN 01J?) that’s to the right of pins 6/7 of the JST connector on either the schematic or gerbers. Is this perhaps some kind of level-shifter or isolation device that’s powered/enabled by CAN_5V or CAN_PWR? I noticed that the 3.3V test point next to it also seems to be controlled by CAN_PWR as well?
Thanks for any insight!