Transmit Holding Register
THR | This field contains data to be transmitted on the serial output port in UART mode. Data should only be written to the THR when the UART_LSR[THRE] is set. If FIFOs are disabled (UART_FCR[FIFOE] set to 0) and UART_LSR[THRE] is set, writing a single character to the THR field clears the UART_LSR[THRE]. Any additional writes to the THR before the UART_LSR[THRE] is set again causes the THR data to be overwritten. If FIFOs are enabled (UART_FCR[FIFOE] set to 1) and UART_LSR[THRE] is set, 32 number of characters of data may be written to the THR before the FIFO is full. Any attempt to write data when the FIFO is full results in the write data being lost. |