
XR16V2550
4
HIGH PERFORMANCE DUART WITH 16-BYTE FIFO
REV. 1.0.3
RXRDYB#
-
18
O
UART channel B Receiver Ready (active low). This output provides the
RX FIFO/RHR status for receive channel B. See
used, leave it unconnected.
MODEM OR SERIAL I/O INTERFACE
TXA
5
7
O
UART channel A Transmit Data or infrared encoder data. Standard
transmit and receive interface is enabled when MCR[6] = 0. In this
mode, the TX signal will be HIGH during reset or idle (no data). Infrared
IrDA transmit and receive interface is enabled when MCR[6] = 1. In the
Infrared mode, the inactive state (no data) for the Infrared encoder/
decoder interface is LOW. If it is not used, leave it unconnected.
RXA
4
5
I
UART channel A Receive Data or infrared receive data. Normal receive
data input must idle HIGH. If this pin is not used, tie it to VCC or pull it
high via a 100k ohm resistor.
RTSA#
23
33
O
UART channel A Request-to-Send (active low) or general purpose out-
put. This output must be asserted prior to using auto RTS flow control,
see EFR[6], MCR[1], and IER[6].
CTSA#
25
38
I
UART channel A Clear-to-Send (active low) or general purpose input.
It can be used for auto CTS flow control, see EFR[7], and IER[7]. This
input should be connected to VCC when not used.
DTRA#
-
34
O
UART channel A Data-Terminal-Ready (active low) or general purpose
output. If it is not used, leave it unconnected.
DSRA#
-
39
I
UART channel A Data-Set-Ready (active low) or general purpose input.
This input should be connected to VCC when not used. This input has
no effect on the UART.
CDA#
-
40
I
UART channel A Carrier-Detect (active low) or general purpose input.
This input should be connected to VCC when not used. This input has
no effect on the UART.
RIA#
-
41
I
UART channel A Ring-Indicator (active low) or general purpose input.
This input should be connected to VCC when not used. This input has
no effect on the UART.
OP2A#
-
32
O
Output Port 2 Channel A - The output state is defined by the user and
through the software setting of MCR[3]. INTA is set to the active mode
and OP2A# output LOW when MCR[3] is set to a logic 1. INTA is set to
the three state mode and OP2A# output HIGH when MCR[3] is set to a
logic 0. See MCR[3]. If INTA is used, this output should not be used as
a general output else it will disturb the INTA output functionality.
TXB
6
8
O
UART channel B Transmit Data or infrared encoder data. Standard
transmit and receive interface is enabled when MCR[6] = 0. In this
mode, the TX signal will be HIGH during reset or idle (no data). Infrared
IrDA transmit and receive interface is enabled when MCR[6] = 1. In the
Infrared mode, the inactive state (no data) for the Infrared encoder/
decoder interface is LOW. If it is not used, leave it unconnected.
RXB
3
4
I
UART channel B Receive Data or infrared receive data. Normal receive
data input must idle HIGH. If this pin is not used, tie it to VCC or pull it
high via a 100k ohm resistor.
Pin Description
NAME
32-QFN
PIN #
48-TQFP
PIN #
TYPE
DESCRIPTION