Hi!
I can run the test simple-test.ino script on both the teensy 3.2 and 4.0, but the single line serial script won't run. Sometimes it gives me some almost random output and glitches, but mostly, it's just black. I have connected the teensy to a mutual ground with the leds and the computer and the correct row of the script is uncommented also. I tried uncommenting the test and deubg rows in the script, but they gave me only glitches. For some time the leds actually displayed the correct output from madmapper, but it was still flickery. What might be the problem?