UTXH = 0x20, // transmit buffer register (little endian, 0x23 for BE)
URXH = 0x24, // receive buffer register (little endian, 0x27 for BE)
UBRDIV = 0x28, // baud rate divisor register
UTXH = 0x20, // transmit buffer register (little endian, 0x23 for BE)
URXH = 0x24, // receive buffer register (little endian, 0x27 for BE)
UBRDIV = 0x28, // baud rate divisor register