```rust
/// Receive data into a u8 buffer. See L44 RM, section 38.5.3: "Character reception procedure"
    pub fn read(&mut self, buf: &mut [u8]) {
        for i in 0..buf.len() {
            // Wait for the next bit
            cfg_if! {
                if #[cfg(not(feature = "f4"))] {
                    while self.regs.isr.read().rxne().bit_is_clear() {}
                    buf[i] = self.regs.rdr.read().rdr().bits() as u8;
                } else {
                    while self.regs.sr.read().rxne().bit_is_clear() {}
                    buf[i] = self.regs.dr.read().dr().bits() as u8;
                }
            }
        }

```