NS16C2552_17 Datasheet, PDF (13/53 Pages) Texas Instruments – Dual Independent UART

NS16C2552, NS16C2752
www.ti.com
Bit
Bit Name
Default
6
Tx Break Ena
5
Forced
Parity Sel
4
Even/Odd
Parity Sel
3
Tx/Rx Parity
Ena
2
Tx/Rx Stop-bit
Length Sel
1:0
Tx/Rx Word
Length Sel
SNLS238D – AUGUST 2006 – REVISED APRIL 2013
Table 10. LCR (0x3) (continued)
R/W
Def
Description
R/W Set Tx Break Enable
0
This bit is the Break Control bit. It causes a break condition to be transmitted to the receiving UART.
The Break Control bit acts only on SOUT and has no effect on the transmitter logic.
1 = Serial output (SOUT) is forced to the Spacing State (break state, logic 0).
0 = The break transmission is disabled (default).
Note: This feature enables the CPU to alert a terminal in a computer communication system. If the
following sequence is followed, no erroneous or extraneous character will be transmitted because of
the break.
1. Load an all 0s, pad character, in response to THRE.
2. Set break after the next THRE.
3. Wait for the transmitter to be idle, (Transmitter Empty TEMT = 1), and clear break when normal
transmission has to be restored.
During the break, the transmitter can be used as a character timer to establish the break duration.
During the break state, any word left in THR will be shifted out of the register but blocked by SOUT
as forced to break state. This word will be lost.
R/W Tx and Rx Forced Parity Select
0
When parity is enabled, this bit selects the forced parity format.
LCR[5] LCR[4] LCR[3]
Parity Select
1
1
1
Force parity to space = 0
1
0
1
Force parity to mark = 1
0
1
1
Even parity
0
0
1
Odd parity
X
X
0
No parity
R/W Tx and Rx Even/Odd Parity Select
0
This bit is only effective when LCR[3]=1. This bit selects even or odd parity format.
1 = Odd parity is transmitted or checked.
0 = Even parity is transmitted or checked (default).
R/W Tx and Rx Parity Enable
0
This bit enables parity generation.
1 = A parity is generated during the data transmission. The receiver checks for parity error of the
data received.
0 = No parity (default).
R/W Tx and Rx Stop-bit Length Select
0
This bit specifies the number of Stop bits transmitted with each serial character.
LCR[2] Word Length Sel Stop-bit Length
1
6,7,8
=2
1
5
= 1.5
0
5,6,7,8
= 1(Default)
Stop-bit length is measured in bit time.
R/W Tx and Rx Word Length Select
0
These two bits specify the word length to be transmitted or received.
LCR[1] LCR[0] Word Length
1
1
=8
1
0
=7
0
1
=6
0
0
= 5 (Default)
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