xr16v554 Exar Corporation, xr16v554 Datasheet - Page 28

• Manufacturer Part Number: xr16v554
• Description: 2.25v To 3.6v Quad Uart With 16-byte Fifo
• Manufacturer: Exar Corporation

XR16V554/554D
2.25V TO 3.6V QUAD UART WITH 16-BYTE FIFO
MSR[4]: CTS Input Status
A HIGH on the CTS# pin will stop UART transmitter as soon as the current character has finished
transmission, and a LOW will resume data transmission. Normally MSR bit-4 bit is the compliment of the CTS#
input. However in the loopback mode, this bit is equivalent to the RTS# bit in the MCR register. The CTS# input
may be used as a general purpose input when the modem interface is not used.
MSR[5]: DSR Input Status
Normally this bit is the complement of the DSR# input. In the loopback mode, this bit is equivalent to the DTR#
bit in the MCR register. The DSR# input may be used as a general purpose input when the modem interface is
not used.
MSR[6]: RI Input Status
Normally this bit is the complement of the RI# input. In the loopback mode this bit is equivalent to bit-2 in the
MCR register. The RI# input may be used as a general purpose input when the modem interface is not used.
MSR[7]: CD Input Status
Normally this bit is the complement of the CD# input. In the loopback mode this bit is equivalent to bit-3 in the
MCR register. The CD# input may be used as a general purpose input when the modem interface is not used.
This is a 8-bit general purpose register for the user to store temporary data.
These registers make-up the value of the baud rate divisor. The concatenation of the contents of DLM and DLL
gives the 16-bit divisor value.
4.10
4.11
Scratch Pad Register (SPR) - Read/Write
Baud Rate Generator Registers (DLL and DLM) - Read/Write
See ”Section 2.8, Programmable Baud Rate Generator” on page 21.
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