Same story this morning. Last night flashed the Arduino FactoryTest. This morning trying to get this thing connected on Windows, which is where I flashed it last night.

Currently, I have not been able to get -TinyGPS++ - examples working. The FIRE has a serial connection and is reading the GPS sentences but is not printing data because the 'valid data' test = FALSE. I have successfully run the -TinyGPS++ - examples on Arduino UNO and DUE no problem. Can any one help with my issue?

@mawg Both the raspberry pi and M5Stack have 3.3v io pins and 5v supply pins. Most M5Stack units and modules have their own 5v >3.3v regulator but in. Take a look at my wip book here. https://github.com/Ajb2k3/UIFlowHandbook/blob/master/UIFlowhandbook.pdf

@ajb2k3 said in Application M5Stack Demo-Board (Factory-Test): Try deleting the circle at the beginning of the line. I've already done that, erased the circle in front of the bracket. But nevertheless it runs only up to function 6! Just found out, that I get the following error message working with Arduino 1.8.9 when I load the code into Arduino !! Error message : "MFRC522_i2C.cpp" contains unknown characters. If the code was created with an older version of Arduino, you might want to use Tool -> Correct Coding & Reload etc. etc. to correct the code. But even afterwards the program runs only up to function 6!

Thank you for your solution! It works!