I got given a Fio V3 but unfortunately the MicroUSB port is missing, not sure why. Is there any other way to program it? I'm thinking perhaps those 6 pins under the microcontroller?


Also can I still power the board? I notice it doesn't have a VCC or RAW pin like the Pro Micro version. I'm not to worried about using a battery, can I plug any matching voltage into the battery plug?

I tried looking through the schematics and tutorials on Sparkfun but don't really know what I'm looking at. Here are some relevant links anyhow:


The board runs at 3.3V, so you can provide 3.3V directly into the 3.3V pin on the side. Also the black connector next to the USB socket is a battery connection for a Li-Ion battery or similar. It will take any voltage between 3.6V and 5V. Any higher and, according to the schematics, you need to remove the solder link that's just below the battery connector (silver blob). With that link removed you can theoretically go up to 20V on the battery input.

Yes, you can program through the 6-pin header below the main chip if you have a suitable hardware programmer (e.g., USBASP). That is a normal ICSP header like most Arduino boards have.


Looking at the hook up guide might help. https://learn.sparkfun.com/tutorials/pro-micro--fio-v3-hookup-guide

The "best" solution might be to try and get the connector replaced, if the pads are still OK. But soldering those connectors is not an easy task.

The datasheet you linked to is the Lion charger, forget about that PDF.

  • 1
    Thanks, yea the pads are no good and I am not very accurate at soldering. I checked that guide but it has no mention what the 6 pins in the middle are. I also found some pins under the Zigbee board labeled DTR and CTS with but it seems they may be the serial connection to the Zigbee (dropbox.com/s/jv5r2c84saajrdv/IMG_20170505_013718.jpg?dl=0).
    – hamstar
    May 4 '17 at 13:36

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