ESD causing Teensy-LC to crash

[Andrew_K]

Hey all,

A friend of mine is making a game with a single button hooked up to a Teensy to tell a computer when the button is pressed. https://lh3.googleusercontent.com/-_pWgE90n4xM/WH-Dz7bOKOI/AAAAAAAAAAg/QYPMyXGTbOcWeeUVVwihLLbdH4AR698BACL0B/h2048/2017-01-18.jpg is a picture of the setup. Very simple circuit, the input checks to see if the switch is high or ground. The source code is literally just checking to see if pin 10 is high or low, and if the button is pressed, it sends a character to a computer via USB. Here is a rough schematic:

Now, the problem he's having is that static discharge on the enclosure, from walking on the carpet, is causing the device to reset. To me it seems like the Teensy is going in to programming mode rather than just resetting. It does the same exact thing when I push the programming button, where only a power cycle will start the program again.

Last night I was doing some ESD testing using a piezo sparking mechanism. The issue seemed to happen when the enclosure was both grounded and not grounded with the Teensy. I noticed that the program pin on the watchdog uC was floating, so I tried tying that high, but the same issue was still happening. It really seems as if it's going in to programming mode. Also, sometimes the Teensy has to be flashed with the program again.

Any ideas?