XR16C2450IJ EXAR [Exar Corporation], XR16C2450IJ Datasheet - Page 18

• Manufacturer Part Number: XR16C2450IJ
• Description: 2.97V TO 5.5V DUART
• Manufacturer: EXAR [Exar Corporation]

XR16C2450
2.97V TO 5.5V DUART
LSR[2]: Receive Data Parity Error Flag
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LSR[3]: Receive Data Framing Error Flag
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LSR[4]: Receive Break Flag
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LSR[5]: Transmit Holding Register Empty Flag
This bit is the Transmit Holding Register Empty indicator. This bit indicates that the transmitter is ready to
accept a new character for transmission. In addition, this bit causes the UART to issue an interrupt to the host
when the THR interrupt enable is set. The THR bit is set to a logic 1 when the data byte is transferred from the
transmit holding register to the transmit shift register. The bit is reset to logic 0 concurrently with the data
loading to the transmit holding register by the host.
LSR[6]: THR and TSR Empty Flag
This bit is set to a logic 1 whenever the transmitter goes idle. It is set to logic 0 whenever either the THR or
TSR contains a data character.
LSR[7]: Reserved
This register provides the current state of the modem interface signals, or other peripheral device that the
UART is connected. Lower four bits of this register are used to indicate the changed information. These bits
are set to a logic 1 whenever a signal from the modem changes state. These bits may be used as general
purpose inputs/outputs when they are not used with modem signals.
MSR[0]: Delta CTS# Input Flag
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MSR[1]: Delta DSR# Input Flag
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MSR[2]: Delta RI# Input Flag
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4.8
Logic 0 = No parity error (default).
Logic 1 = Parity error. The receive character in RHR does not have correct parity information and is suspect.
This error is associated with the character available for reading in RHR. If the LSR interrupt is enabled (IER
bit-2), an interrupt will be generated when the character is in the RHR.
Logic 0 = No framing error (default).
Logic 1 = Framing error. The receive character did not have a valid stop bit(s). This error is associated with
the character available for reading in RHR. If the LSR interrupt is enabled (IER bit-2), an interrupt will be
generated when the character is in the RHR.
Logic 0 = No break condition (default).
Logic 1 = The receiver received a break signal (RX was a logic 0 for at least one character frame time). The
break indication remains until the RX input returns to the idle condition, “mark” or logic 1. If the LSR interrupt
is enabled (IER bit-2), an interrupt will be generated when the character is in the RHR.
Logic 0 = No change on CTS# input (default).
Logic 1 = The CTS# input has changed state since the last time it was monitored. A modem status interrupt
will be generated if MSR interrupt is enabled (IER bit-3).
Logic 0 = No change on DSR# input (default).
Logic 1 = The DSR# input has changed state since the last time it was monitored. A modem status interrupt
will be generated if MSR interrupt is enabled (IER bit-3).
Logic 0 = No change on RI# input (default).
Logic 1 = The RI# input has changed from a logic 0 to a logic 1, ending of the ringing signal. A modem status
interrupt will be generated if MSR interrupt is enabled (IER bit-3).
Modem Status Register (MSR) - Read Only
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xr
REV. 1.0.0