PWM Channel Initialization Function: pwm_init()

The function "pwm_init" is used to initialize the PWM channel with the specified frequency and duty cycle.\n\nParameters:\n- pwmch: The PWM channel to be initialized (PWMCH_enum type)\n- freq: The desired frequency of the PWM signal in Hz (uint32 type)\n- duty: The desired duty cycle of the PWM signal in percentage (uint32 type)\n\nReturn Type: void\n\nExample usage:\npwm_init(PWMCH0, 1000, 50);\nThis initializes PWM channel 0 with a frequency of 1000 Hz and a duty cycle of 50%.