Posted on May 17, 2011 at 14:09Well there is ''one'' register in terms of the address presented for you to read and write, but in terms of the hardware you are writing to a TX buffer register (which is moved to the TX shift register when the last bit shifts out), and reading from a different RX buffer register (which is loaded from the RX shift register when the last bit has shifted in).
They are independent, but share the same IO address. The USARTs are full duplex.
