LM3S1439_16 Datasheet, PDF (452/699 Pages) Texas Instruments – Stellaris LM3S1439 Microcontroller

Universal Asynchronous Receivers/Transmitters (UARTs)
Bit/Field
3:0
Name
reserved
Type
RO
Reset
0x00
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
452
July 15, 2014
Texas Instruments-Production Data