You are reading a single comment by @Gordon and its replies.
Click here to read the full conversation.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
@Gordon
Ok, so all you need to do is connect the two GNDs (STM32F4 GND and PIC GND) together and it should work...