Texas Instruments AM335 Series Technical Reference Manual

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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 Figure 19-79 and described in
Table 19-78.
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
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Texas Instruments AM335 Series Specifications

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Brand	Texas Instruments
Model	AM335 Series
Category	Computer Hardware
Language	English