Transmit Holding Register. The next character to be transmitted is written here (DLAB =0).
THR | Writing to the UART4 Transmit Holding Register causes the data to be stored in the UART4 transmit FIFO. The byte will be sent when it reaches the bottom of the FIFO and the transmitter is available. |
RESERVED | Reserved. Read value is undefined, only zero should be written. |