# Expansion Board 3.0

![](/files/-LKN82ULDMpUs0Lnq1Kx)

## Pinout

The pinout of the Expansion Board is available as a PDF File

{% file src="/files/-LKN82UNLD-yPfdRcqkf" %}
Expansion Board 3 Pinout
{% endfile %}

![](/files/-LKN82UP8jyni4aNzuiy)

{% hint style="danger" %}
Be gentle when plugging/unplugging from the USB connector. Whilst the USB connector is soldered and is relatively strong, if it breaks off it can be very difficult to fix.
{% endhint %}

## Battery Charger

The Expansion Board features a single cell Li-Ion/Li-Po charger. When the board is being powered via the micro USB connector, the Expansion Board will charge the battery (if connected). When the `CHG` jumper is present the battery will be charged at `450mA`. If this value is too high for your application, removing the jumper lowers the charge current to `100mA`.

## Specsheets

The specsheet of the Expansion Board is available as a PDF File.

{% file src="/files/-LKN82UR2MbYnX\_qRN9t" %}
Expansion Board 3 Datasheet
{% endfile %}

## Differences between v2.0 and v3.0

* The FTDI chip as been replaced with a custom programmed PIC like on the

  Pysense/Pytrack/Pyscan boards. This allows our firmware update tool to

  automatically put the module into bootloader mode.
* Added a "Safe boot" button to enter safe boot easier. This button connects

  `P12` to `3.3v` and if pressed and held while the reset button is pressed on

  a Pycom module, the module will enter safe boot.

## Troubleshooting

* If PIC stays in bootloader mode, the [`dfu-util` update](/pytrack-pysense-pyscan/installation/firmware.md) should be performed


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