Also can lithium charger charge 2-cell lithium batteries or only 1-cell?

Is the external crystal(32kHz) Clock set as default in the Arduino DF Robot build? This is an awful pain to change using ESp-IDF!!!

What is this SD card library in the C3 tutorials? Built in? The standard Sd.h? A specific library? You don't give any information!

Hi, The thickness is 3.5mm without the USB interface, and the maximum thickness is 4.6mm with the USB interface

Wish it was a 24pin FPC connector for e-ink EPDs…

Does this board work with PlatformIO in VSCode? I'm having trouble getting the Serial output to print to any monitor. Works with the Arduino 2.0 IDE.