Hi!
Some pins of my Teensy3.5 give random output even with internal pullups enabled. Here is a diagram of my project:
There are 2 metal enclosures (relatively big), one of them contains the PSU. Plus and minus of the PSU go to both teensies (minus goes to GND), so the Teensies GNDs are not connected to mains earth. One enclosure is connected to mains earth, the other enclosure is connected to the first enclosure. The USB cable shields are only connect at one side, so no connection of the shield to GND (but all 4 USB lines are connected, and the VUSB pad is disconnected).
Now, if I connect the Teensy3.5 via USB to my PC some pins (not all) start to flip randomly. It seems I can stop this by connecting GND to mains earth (marked in red), but I am not sure if it's OK to do so...
Please let me know how to best layout the GND and earth connections!
Some pins of my Teensy3.5 give random output even with internal pullups enabled. Here is a diagram of my project:
There are 2 metal enclosures (relatively big), one of them contains the PSU. Plus and minus of the PSU go to both teensies (minus goes to GND), so the Teensies GNDs are not connected to mains earth. One enclosure is connected to mains earth, the other enclosure is connected to the first enclosure. The USB cable shields are only connect at one side, so no connection of the shield to GND (but all 4 USB lines are connected, and the VUSB pad is disconnected).
Now, if I connect the Teensy3.5 via USB to my PC some pins (not all) start to flip randomly. It seems I can stop this by connecting GND to mains earth (marked in red), but I am not sure if it's OK to do so...
Please let me know how to best layout the GND and earth connections!