Function sigmadelta_set_duty

pub unsafe extern "C" fn sigmadelta_set_duty(
    channel: u32,
    duty: i8,
) -> i32

@brief Set Sigma-delta channel duty.

   This function is used to set Sigma-delta channel duty,
   If you add a capacitor between the output pin and ground,
   the average output voltage will be Vdc = VDDIO / 256 * duty + VDDIO/2,
   where VDDIO is the power supply voltage.

@param channel Sigma-delta channel number @param duty Sigma-delta duty of one channel, the value ranges from -128 to 127, recommended range is -90 ~ 90. The waveform is more like a random one in this range.

@return - ESP_OK Success - ESP_ERR_INVALID_STATE sigmadelta driver has not been initialized - ESP_ERR_INVALID_ARG Parameter error