Hardware Test PCB
Appearance
https://gitlab.postmarketos.org/postmarketOS/postmarketos/-/issues/63
UART level-shifting
https://gitlab.postmarketos.org/postmarketOS/postmarketos/-/issues/63#note_1941713275
Pi Zero Socket
Buck Converter
- Requirements
- A 12V-in barrel jack which powers a buck converter with ~3.8-9v 4A output. This will be used to power phones running without a battery
- A software-controllable way to adjust voltage on the buck converter
TODO: add caleb's off the shelf integrated one?
TODO: Ask Luca about FP2 mobo project that also replaces battery
LT3690
To change the voltage, we need to change the resistance (See page 12). To meet requirements, we need to change the resistance in the resistor network which can be done using a digital potentiometer:
https://www.analog.com/media/en/technical-documentation/data-sheets/AD5293.pdf
To ensure voltage output is accurate, make sure tolerance of pot is 1%.
https://en.wikipedia.org/wiki/Digital_potentiometer#Limitations
TODO: research disadvantages of digital pot