Both the fan and servo are controlled with a PWM signal. In the STM32WB55 microcontroller, there are two timers capable of generating PWM signals. One of them is connected to the RGB LED, second is connected to the fan and servo.

In the stm32duino examples ¹⁾, there is a simple program which allows us to control a single LED with PWM. It is named “All-in-one_setPWM” ²⁾. It uses hardware timer output connected directly to an LED. We will modify this example to control the fan and servo. The code is composed of two files FanSrvTest.h and FanSrvTest.cpp. In the *.h file some definitions are