Most efficient code to generate pwm

https://github.com/arduino/ArduinoCore-avr/blob/master/cores/arduino/Arduino.h

Thanks

Fun fact, if you drive a Neopixel LED with PWM, you need a frequency between 20 kHz to 800 kHz

Yeah I do that all the time with my UNO.

a7

The Neopixel library for the Uno doesn't use PWM...