ST16C2550CQ48 EXAR [Exar Corporation], ST16C2550CQ48 Datasheet - Page 22

• Manufacturer Part Number: ST16C2550CQ48
• Description: 2.97V TO 5.5V DUART WITH 16-BYTE FIFO
• Manufacturer: EXAR [Exar Corporation]

ST16C2550
2.97V TO 5.5V DUART WITH 16-BYTE FIFO
LCR[5]: TX and RX Parity Select
If the parity bit is enabled, LCR BIT-5 selects the forced parity format.
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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.
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LCR[7]: Baud Rate Divisors (DLL/DLM) Enable
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The MCR register is used for controlling the serial/modem interface signals or general purpose inputs/outputs.
MCR[0]: DTR# Output
The DTR# pin is a modem control output. If the modem interface is not used, this output may be used as a
general purpose output.
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MCR[1]: RTS# Output
The RTS# pin is a modem control output. If the modem interface is not used, this output may be used as a
general purpose output.
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MCR[2]: Reserved
OP1# is not available as an output pin on the C2550. But it is available for use during Internal Loopback Mode.
In the Loopback Mode, this bit is used to write the state of the modem RI# interface signal.
4.7
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.
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.
Logic 0 = Data registers are selected (default).
Logic 1 = Divisor latch registers are selected.
Logic 0 = Force DTR# output to a logic 1 (default).
Logic 1 = Force DTR# output to a logic 0.
Logic 0 = Force RTS# output to a logic 1 (default).
Logic 1 = Force RTS# output to a logic 0.
Modem Control Register (MCR) or General Purpose Outputs Control - Read/Write
LCR B
X
0
0
1
1
IT
-5 LCR B
X
0
1
0
1
T
IT
ABLE
-4 LCR B
10: P
0
1
1
1
1
IT
ARITY SELECTION
-3
22
Forced parity to space, “0”
Force parity to mark, “1”
P
ARITY SELECTION
Even parity
Odd parity
No parity
xr
REV. 4.4.0