Registers
1515
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Universal Asynchronous Receiver/Transmitter (UART)
31.3 Registers
The system programmer has access to and control over any of the UART registers that are listed in
. These registers, which control UART operations, receive data, and transmit data, are available
at 32-bit addresses in the device memory map. See your device-specific data manual for the memory
address of these registers.
•
RBR, THR, and DLL share one address. When the DLAB bit in LCR is 0, reading from the address
gives the content of RBR, and writing to the address modifies THR. When DLAB = 1, all accesses at
the address read or modify DLL. DLL can also be accessed with address offset 20h.
•
IER and DLH share one address. When DLAB = 0, all accesses read or modify IER. When DLAB = 1,
all accesses read or modify DLH. DLH can also be accessed with address offset 24h.
•
IIR and FCR share one address. Regardless of the value of the DLAB bit, reading from the address
gives the content of IIR, and writing modifies FCR.
Table 31-6. UART Registers
Offset
Acronym
Register Description
Section
0h
RBR
Receiver Buffer Register (read only)
0h
THR
Transmitter Holding Register (write only)
4h
IER
Interrupt Enable Register
8h
IIR
Interrupt Identification Register (read only)
8h
FCR
FIFO Control Register (write only)
Ch
LCR
Line Control Register
10h
MCR
Modem Control Register
14h
LSR
Line Status Register
18h
MSR
Modem Status Register
1Ch
SCR
Scratch Pad Register
20h
DLL
Divisor LSB Latch
24h
DLH
Divisor MSB Latch
28h
REVID1
Revision Identification Register 1
2Ch
REVID2
Revision Identification Register 2
30h
PWREMU_MGMT
Power and Emulation Management Register
34h
MDR
Mode Definition Register