UART Registers
19.5.1.46 UART Autobauding Status Register (UASR)
The UART autobauding status register (UASR) returns the speed, the number of bits by characters, and
the type of parity in UART autobauding mode. In autobauding mode, the input frequency of the UART
modem must be fixed to 48 MHz. Any other module clock frequency results in incorrect baud rate
recognition. The UART autobauding status register (UASR) is shown in
and described in
.
NOTE:
•
This register is used to set up transmission according to characteristics of previous
reception, instead of LCR, DLL, and DLH registers when UART is in autobauding mode.
•
To reset the autobauding hardware (to start a new “AT” detection) or to set the UART in
standard mode (no autobaud), MDR1[2:0] must be set to 7h (reset state), then set to 2h
(UART in autobaud mode) or cleared to 0 (UART in standard mode).
Usage limitation:
•
Only 7 and 8 bits character (5 and 6 bits not supported).
•
7 bits character with space parity not supported.
•
Baud rate between 1200 and 115 200 bp/s (10 possibilities).
Figure 19-79. UART Autobauding Status Register (UASR)
15
8
7
6
5
4
0
Reserved
PARITYTYPE
BITBYCHAR
SPEED
R-0
R-0
R-0
R-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 19-78. UART Autobauding Status Register (UASR) Field Descriptions
Bit
Field
Value
Description
15-8
Reserved
0
Reserved.
7-6
PARITYTYPE
0-3h
Type of the parity in UART autobauding mode.
0
No parity identified
1h
Parity space
2h
Even parity
3h
Odd parity
5
BITBYCHAR
Number of bits by characters.
0
7-bit character identified.
1
8-bit character identified.
4-0
SPEED
0-1Fh
Speed
0
No speed identified.
1h
115 200 baud
2h
57 600 baud
3h
38 400 baud
4h
28 800 baud
5h
19 200 baud
6h
14 400 baud
7h
9600 baud
8h
4800 baud
9h
2400 baud
Ah
1200 baud
Bh-1Fh
Reserved
3542
Universal Asynchronous Receiver/Transmitter (UART)
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated