Functional Description
19.3.8.1.2 Choosing the Appropriate Divisor Value
Two divisor values are:
•
UART 16x mode: Divisor value = Operating frequency/(16x baud rate)
•
UART 13x mode: Divisor value = Operating frequency/(13x baud rate)
describes the UART baud rate settings.
Table 19-25. UART Baud Rate Settings (48-MHz Clock)
Baud Rate
Baud Multiple
DLH,DLL (Decimal)
DLH,DLL (Hex)
Actual Baud Rate
Error (%)
0.3 kbps
16x
10000
0x27, 0x10
0.3 kbps
0
0.6 kbps
16x
5000
0x13, 0x88
0.6 kbps
0
1.2 kbps
16x
2500
0x09, 0xC4
1.2 kbps
0
2.4 kbps
16x
1250
0x04, 0xE2
2.4 kbps
0
4.8 kbps
16x
625
0x02, 0x71
4.8 kbps
0
9.6 kbps
16x
312
0x01, 0x38
9.6153 kbps
+0.16
14.4 kbps
16x
208
0x00, 0xD0
14.423 kbps
+0.16
19.2 kbps
16x
156
0x00, 0x9C
19.231 kbps
+0.16
28.8 kbps
16x
104
0x00, 0x68
28.846 kbps
+0.16
38.4 kbps
16x
78
0x00, 0x4E
38.462 kbps
+0.16
57.6 kbps
16x
52
0x00, 0x34
57.692 kbps
+0.16
115.2 kbps
16x
26
0x00, 0x1A
115.38 kbps
+0.16
230.4 kbps
16x
13
0x00, 0x0D
230.77 kbps
+0.16
460.8 kbps
13x
8
0x00, 0x08
461.54 kbps
+0.16
921.6 kbps
13x
4
0x00, 0x04
923.08 kbps
+0.16
1.843 Mbps
13x
2
0x00, 0x02
1.846 Mbps
+0.16
3.6884 Mbps
13x
1
0x00, 0x01
3.6923 Mbps
+0.16
19.3.8.1.3 UART Data Formatting
The UART can use hardware flow control to manage transmission and reception. Hardware flow control
significantly reduces software overhead and increases system efficiency by automatically controlling serial
data flow using the RTS output and CTS input signals.
The UART is enhanced with the autobauding function. In control mode, autobauding lets the speed, the
number of bits per character, and the parity selected be set automatically.
19.3.8.1.3.1 Frame Formatting
When autobauding is not used, frame format attributes must be defined in the UARTi.UART_LCR register.
Character length is specified using the UARTi.UART_LCR[1:0] CHAR_LENGTH bit field.
The number of stop-bits is specified using the UARTi.UART_LCR[2] NB_STOP bit.
The parity bit is programmed using the UARTi.UART_LCR[5:3] PARITY_EN, PARITY_TYPE_1, and
PARITY_TYPE_2 bit fields (see
Table 19-26. UART Parity Bit Encoding
PARITY_EN
PARITY_TYPE_1
PARITY_TYPE_2
Parity
0
N/A
N/A
No parity
1
0
0
Odd parity
1
1
0
Even parity
1
0
1
Forced 1
1
1
1
Forced 0
3475
SPRUH73H – October 2011 – Revised April 2013
Universal Asynchronous Receiver/Transmitter (UART)
Copyright © 2011–2013, Texas Instruments Incorporated