Advanced I/O Controller with Motherboard GLUE Logic
Datasheet
These two bits specify the number of bits in each transmitted or received serial character. The encoding of
bits 0 and 1 is as follows:
The Start, Stop and Parity bits are not included in the word length.
BIT 1
BIT 0
WORD LENGTH
5 Bits
0
0
1
1
0
1
0
1
6 Bits
7 Bits
8 Bits
Bit 2
This bit specifies the number of stop bits in each transmitted or received serial character. The following
table summarizes the information.
NUMBER OF
STOP BITS
BIT 2 WORD LENGTH
0
1
1
1
1
--
1
1.5
2
2
2
5 bits
6 bits
7 bits
8 bits
Note: The receiver will ignore all stop bits beyond the first, regardless of the number used in transmitting.
Bit 3
Parity Enable bit. When bit 3 is a logic “1”, a parity bit is generated (transmit data) or checked (receive
data) between the last data word bit and the first stop bit of the serial data. (The parity bit is used to
generate an even or odd number of 1s when the data word bits and the parity bit are summed).
Bit 4
Even Parity Select bit. When bit 3 is a logic “1” and bit 4 is a logic “0”, an odd number of logic “1”’s is
transmitted or checked in the data word bits and the parity bit. When bit 3 is a logic “1” and bit 4 is a logic
“1” an even number of bits is transmitted and checked.
Bit 5
This bit is the Stick Parity bit. When parity is enabled it is used in conjunction with bit 4 to select Mark or
Space Parity. When LCR bits 3, 4 and 5 are 1 the Parity bit is transmitted and checked as a 0 (Space
Parity). If bits 3 and 5 are 1 and bit 4 is a 0, then the Parity bit is transmitted and checked as 1 (Mark
Parity). If bit 5 is 0 Stick Parity is disabled.
Bit 6
Set Break Control bit. When bit 6 is a logic “1”, the transmit data output (TXD) is forced to the Spacing or
logic “0” state and remains there (until reset by a low level bit 6) regardless of other transmitter activity.
This feature enables the Serial Port to alert a terminal in a communications system.
SMSC LPC47M182
83
Revision 1.8 SMSC/Non-SMSC Register Sets (02-24-05)
DATASHEET
SMSC [ SMSC CORPORATION ]
