dkadish / BioAcousticIndexTool

Smart sensor to calculate acoustic indices and capture environmental data in the field.

MIT License

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Test Teensy operation without USB_VIN #42

Open dkadish opened 4 months ago

dkadish commented 4 months ago

I'm not sure how to connect V_USB_IN (fused, dioded supply from USB) to the Teensy/MicroMod USB_VIN pin.

Teensy uses USB_VIN for power and I'm not sure that USB communication/programming will work without it. But that would kind of defeat the point of disconnecting USB power.

At the very least, I need to move the connection to behind the diode and make a solderable disconnect, possibly a jumper...

dkadish commented 4 months ago

Conflicting information here. From the schematics, it seems like V_USB isn't necessary to run. But it seems (https://forum.pjrc.com/index.php?threads/teensy-4-1-powered-from-3-3v-pin-not-initializing-usb-communication.73613/) like it might be necessary for it to have 3.3V or 5V or nothing.

Resources

https://www.pjrc.com/store/ic_mkl02_t4.html

Takeaways

V_BATT should be powered first. Might need to use the coin cell even if not using the RTC

To cover my ass: Connect V_USB_IN (pre-diode), 3.3V, and possibly V+ behind diodes and a solder/real jumper to USB_VIN on the Teensy

dkadish commented 4 months ago

https://forum.pjrc.com/index.php?threads/powering-micromod-from-3-3v.68305/ is a good account of what happens with MM

dkadish commented 4 months ago

From https://forum.pjrc.com/index.php?threads/powering-micromod-from-3-3v.68305/:

I removed the F2 fuse and left BYP open on the ATP carrier. I connected external power (3.3V) to V_IN on the ATP.
I left the MEAS jumper in place on the Teensy Micromod
I have a Coin Cell installed on the ATP (if that matters).