ST16C654D Exar Corporation, ST16C654D Datasheet - Page 30

• Manufacturer Part Number: ST16C654D
• Description: St16c654d -quad Uart With 64-byte Fifo And Infrared Irda Encoder/decoder
• Manufacturer: Exar Corporation

ST16C654/654D
2.97V TO 5.5V QUAD UART WITH 64-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 Enable
Baud rate generator divisor (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 and may be used for automatic hardware flow control by enabled by
EFR bit-6. 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 654. 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 BIT-5 = logic 0, parity is not forced (default).
LCR BIT-5 = logic 1 and LCR BIT-4 = logic 0, parity bit is forced to a logical 1 for the transmit and receive
data.
LCR BIT-5 = logic 1 and LCR BIT-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
T
ABLE
X
0
1
0
1
IT
-4 LCR B
13: P
ARITY SELECTION
30
0
1
1
1
1
IT
-3
Force parity to mark,
P
Forced parity to
ARITY SELECTION
Even parity
Odd parity
space, “0”
No parity
“1”
xr
REV. 5.0.2