pub fn nr21(&self) -> u8 {
        let duty = self.sound2.duty().into_field();

        duty << 6 | 0x3f
    }
/// Retreive sound 2 duty cycle. Length field is write only.
Retreive sound 2 duty cycle. Length field is write only.
Retreive sound 2 duty cycle . Length field is write only .
pub fn nr21(&self) -> u8 {
        let duty = self.sound2.duty().into_field();
        duty << 6 | 0x3f
    }
pub fn nr21 ( & self ) -> u8 { let duty = self . sound2 . duty ( ) . into_field ( ) ; duty << 6 | 0x3f }
Retreive sound 2 duty cycle.
Retreive sound 2 duty cycle .
&self
&self