UART Registers
19.5.1.10 Line Control Register (LCR)
The line control register (LCR) is shown in
and described in
.
NOTE:
As soon as LCR[6] is set to 1, the TX line is forced to 0 and remains in this state as long as
LCR[6] = 1.
Figure 19-43. Line Control Register (LCR)
15
8
Reserved
R-0
7
6
5
4
3
2
1
0
DIV_EN
BREAK_EN
PARITY_TYPE2
PARITY_TYPE1
PARITY_EN
NB_STOP
CHAR_LENGTH
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 19-39. Line Control Register (LCR) Field Descriptions
Bit
Field
Value
Description
15-8
Reserved
0
Reserved.
7
DIV_EN
Divisor latch enable.
0
Normal operating condition.
1
Divisor latch enable. Allows access to DLL and DLH.
6
BREAK_EN
Break control bit.
Note: When LCR[6] is set to 1, the TX line is forced to 0 and remains in this state as long as
LCR[6] = 1.
0
Normal operating condition.
1
Forces the transmitter output to go low to alert the communication terminal.
5
PARITY_TYPE2
If LCR[3] = 1:
0
If LCR[5] = 0, LCR[4] selects the forced parity format.
1
If LCR[5] = 1 and LCR[4] = 0, the parity bit is forced to 1 in the transmitted and received data.
1
If LCR[5] = 1 and LCR[4] = 1, the parity bit is forced to 0 in the transmitted and received data.
4
PARITY_TYPE1
If LCR[3] = 1:
0
Odd parity is generated.
1
Even parity is generated.
3
PARITY_EN
Parity bit.
0
No parity.
1
A parity bit is generated during transmission, and the receiver checks for received parity.
2
NB_STOP
Specifies the number of stop bits.
0
1 stop bit (word length = 5, 6, 7, 8).
1
1.5 stop bits (word length = 5) or 2 stop bits (word length = 6, 7, 8).
1-0
CHAR_LENGTH
0-3h
Specifies the word length to be transmitted or received.
0
5 bits
1h
6 bits
2h
7 bits
3h
8 bit
3515
SPRUH73H – October 2011 – Revised April 2013
Universal Asynchronous Receiver/Transmitter (UART)
Copyright © 2011–2013, Texas Instruments Incorporated