Direct

Latency of directly hooking an input to a digital pin on a microcontroller

Measured by toggling a pin on the microcontroller in question, and then timing how long it takes for that signal to reach a target over USB.

Microcontroller	Pi Pico	Sparkfun Pro Micro 5V	Sparkfun Pro Micro 3.3V	Arduino Uno	Pi Pico	Sparkfun Pro Micro 5V	Sparkfun Pro Micro 3.3V	Arduino Uno
Firmware	new	new	new	new	old	old	old	old
Usb Poll Rate	1 ms	1 ms	1 ms	1 ms	1 ms	1 ms	1ms	1 ms
Minimum	0.53 ms	0.53 ms	0.53 ms	0.48 ms	1.32 ms	0.54 ms	0.73 ms	0.92 ms
Maximum	1.34 ms	1.34 ms	1.35 ms	1.3 ms	2.15 ms	1.36 ms	1.97 ms	1.96 ms
Average	0.84 ms	0.84 ms	0.84 ms	0.8 ms	1.79 ms	0.86 ms	1.26 ms	1.42 ms
Std dev	0.24 ms	0.24 ms	0.24 ms	0.25 ms	0.22 ms	0.25 ms	0.31 ms	0.3 ms
%on time	96%	96%	96%	96%	90%	96%	93%	92%
%1f skip	4%	4%	4%	4%	10%	4%	7%	8%
%2f skip	0%	0%	0%	0%	0%	0%	0%	0%
%3f skip	0%	0%	0%	0%	0%	0%	0%	0%

Note that in the below graph, you can click on legends to show and hide different controllers when comparing.