Unprotected LiPo cell overcharging
Symptom: you have a MightyHat R3, and using it with an unprotected LiPo cell (bare cell without embedded protection circuitry). Depending on the USB voltage, the battery might charge to above the recommended 4.2V for LiPo cells.
Solution: It is recommended at least until R4 is released to use LiPo cells with embedded protection circuitry, as that is a double protection that guards against several faults, not just overcharging.
Pi screen full of junk / corrupt text at first boot
Symptom: with your MightyHat attached, instead of booting to a login prompt, the Pi console produces endless junk text output. This is because:
- by default the Raspbian images enable the GPIO serial console and will start sending output to the GPIO serial port (the
- the MightyHat serial port is hardwired to the Pi header and once programmed, it will respond to serial input from the Pi side. The Pi will then try to interpret the incoming serial text from the Pi resulting in an endless loop
Solution: the serial link must be interrupted until you can login and disable the serial console via the
raspi-config utility. There are a few ways to achieve this:
- setup your Pi before you attach the MightyHat to it, disable the GPIO serial console via
raspi-configand only then attach the MightyHat
- if the MightyHat cannot be removed, you can hold the tactile RESET button on the MightyHat (this ensures the MightyHat is not active and the serial port is disabled) while the Pi boots to the login prompt, then run
raspi-configto disable the serial console, once that is done you can release the MightyHat RESET button