khoih-prog/AVR_Slow_PWM
This library enables you to use ISR-based PWM channels on AVR-based boards, such as Mega-2560, UNO,Nano, Leonardo, etc., to create and output PWM any GPIO pin. It now supports 16 ISR-based PWM channels, while consuming only 1 Hardware Timer. PWM channel interval can be very long (ulong microsecs / millisecs). The most important feature is they're ISR-based PWM channels, supporting lower PWM frequencies with suitable accuracy. Their executions are not blocked by bad-behaving functions or tasks. This important feature is absolutely necessary for mission-critical tasks. These ISR-based PWMs, still work even if other software functions are blocking. Moreover, they are much more precise (certainly depending on clock frequency accuracy) than other software-based PWM using millis() or micros(). That's necessary if you need to control devices requiring high precision