delay of nanosecond Teensy ?

[aybiki]

is it so possible to make a delay of nanosecond between a low and high state with a teensy 3.6 seen that its frequency 180 MHZ ?

[MarkT]

I don't think the pin drivers can go that fast even if given a 500MHz signal... Typical external CMOS pins have rise- and fall- times of a few ns.
For faster you need impedance matched LVDS or similar - this is into the microwave frequency domain, everything needs to be a transmission
line.

[aybiki]

experimentally with the microsecond delay function I can go down to 7 microseconds after remaining constant!

[PaulStoffregen]

Here's a thread about fast I/O on Teensy 3.6 which might help. In particular, look for the info about disabling slew rate limiting (which normally you would want, as it greatly reduces high frequency noise & other undesirable effects).

https://forum.pjrc.com/threads/41874...l=1#post132347

And here is similar info for Teensy 4

https://forum.pjrc.com/threads/57185...l=1#post212236