
XR16L2552
2.25V TO 5.5V DUART WITH 16-BYTE FIFO
xr
REV. 1.1.1
28
LCR[3]: TX and RX Parity Select
Parity or no parity can be selected via this bit. The parity bit is a simple way used in communications for data
integrity check. See
Table 11
for parity selection summary below.
Logic 0 = No parity.
Logic 1 = A parity bit is generated during the transmission while the receiver checks for parity error of the
data character received.
LCR[4]: TX and RX Parity Select
If the parity bit is enabled with LCR bit-3 set to a logic 1, LCR BIT-4 selects the even or odd parity format.
Logic 0 = ODD Parity is generated by forcing an odd number of logic 1’s in the transmitted character. The
receiver must be programmed to check the same format (default).
Logic 1 = EVEN Parity is generated by forcing an even number of logic 1’s in the transmitted character. The
receiver must be programmed to check the same format.
LCR[5]: TX and RX Parity Select
If the parity bit is enabled, LCR BIT-5 selects the forced parity format.
LCR[5] = logic 0, parity is not forced (default).
LCR[5] = logic 1 and LCR[4] = logic 0, parity bit is forced to a logical 1 for the transmit and receive data.
LCR[5] = logic 1 and LCR[4] = logic 1, parity bit is forced to a logical 0 for the transmit and receive data.
LCR[6]: Transmit Break Enable
When enabled, the Break control bit causes a break condition to be transmitted (the TX output is forced to a
“space’, logic 0, state). This condition remains, until disabled by setting LCR bit-6 to a logic 0.
Logic 0 = No TX break condition (default).
Logic 1 = Forces the transmitter output (TX) to a “space”, logic 0, for alerting the remote receiver of a line
break condition.
LCR[7]: Baud Rate Divisors Enable
Baud rate generator divisor (DLL/DLM) enable.
Logic 0 = Data registers are selected (default).
Logic 1 = Divisor latch registers are selected.
4.8
The MCR register is used for controlling the serial/modem interface signals or general purpose inputs/outputs.
Modem Control Register (MCR) or General Purpose Outputs Control - Read/Write
T
ABLE
11: P
ARITY
SELECTION
LCR B
IT
-5 LCR B
IT
-4 LCR B
IT
-3
P
ARITY
SELECTION
X
X
0
No parity
0
0
1
Odd parity
0
1
1
Even parity
1
0
1
Force parity to mark,
“1”
1
1
1
Forced parity to
space, “0”