UART/IrDA Control and Status Registers
12-55
UART Devices
The receiver section consists of the receiver holding register (RHR) and the
receiver shift register. The RHR is actually a 64-byte FIFO. The receiver shift
register receives serial data from RX input. The data is converted to parallel
data and moved to the RHR. If the FIFO is disabled, location zero of the FIFO
is used to store the single data character. If overflow occurs, data in the RHR
is not overwritten.
Table 12–45. Receive Holding Register (RHR)
Bit
Name
Function
R/W
Reset
Value
7–0
RHR
Receive holding register
R
Undefined
The transmitter section consists of the transmit holding register (THR) and the
transmit shift register. The THR is actually a 64-byte FIFO. The host (MPU or
DSP) writes data to the THR. The data is placed into the transmit shift register,
where it is shifted out serially on the TX output. If the FIFO is disabled, location
0 of the FIFO is used to store the data.
Table 12–46. Transmit Holding Register (THR)
Bit
Name
Function
R/W
Reset
Value
7–0
THR
Transmit holding register
W
Undefined