In the Teensy 4.0 the direction and pin number is fixed. I.e. you have to use pin 0 for input and pin 1 for output. In the Teensy 3.x systems, there are additional pins that can be used, but these also are fixed in terms of the pin number.I've tried to use Pins 0 and 1 of the Teensy 4.0
I can use Pin 1 but only as input, and Pin 0 only as Output (not as Input)
But I can not use pinMode for these pins. Is there a specific reason?
Yes, because at present the other USB modes haven't been ported to the Teensy 4.0. Evidently this is at the top of Paul's priority list, so I imagine Teensydunion 1.49 will support it. Having the other modes would allow the Teensy to act as a USB keyboard/mount, or USB raw HID device (among other options).I
In the Arduino Teensy 4.0 Settings menu I can also not disable "Serial"