Универсальный асинхронный приемо-передатчик: список регистров

  Unused

  THR

Transmit Holding Register
Data be transmitted on the serial output port (sout) in UART mode or the
serial infrared output (sir_out_n) in infrared mode. Data should only be
written to the THR when the THR Empty (THRE) bit (LSR[5]) is set.
If in FIFO mode and FIFOs are enabled (FCR[0] = 1) and THRE is set, 16
number of characters data may be written to the THR before the FIFO is full.
When the FIFO is full, any write data results in the write data being lost.

Команда U-Boot для чтения регистра

Bit fields structure

typedef union  uart_thr
{
  struct
  {
   unsigned thr : 8;
   unsigned unused0 : 24;
  } b;
   unsigned long w;
} UART_THR