XR16L2551_07 Datasheet, PDF (4/49 Pages) Exar Corporation – LOW VOLTAGE DUART WITH POWERSAVE

XR16L2551
LOW VOLTAGE DUART WITH POWERSAVE
Pin Description
REV. 1.1.3
NAME
32-QFN
PIN #
48-TQFP
PIN #
TYPE
DESCRIPTION
INTB
21
(NC)
TXRDYA#
-
RXRDYA#
-
29
O When 16/68# pin is at logic 1 for Intel bus interface, this output
becomes channel B interrupt output. The output state is defined by the
user and through the software setting of MCR[3]. INTB is set to the
active mode and OP2B# output to a logic 0 when MCR[3] is set to a
logic 1. INTB is set to the three state mode and OP2B# to a logic 1
when MCR[3] is set to a logic 0. See MCR[3].
When 16/68# pin is at logic 0 for Motorola bus interface, this output is
not used and will stay at logic zero level. Leave this output uncon-
nected.
43
O ^{UART channel A Transmitter Ready (active low). The output}
provides the TX FIFO/THR status for transmit channel A. If it is
not used, leave it unconnected.
31
O UART channel A Receiver Ready (active low). This output provides the
RX FIFO/RHR status for receive channel A. If it is not used, leave it
unconnected.
TXRDYB#
-
6
O UART channel B Transmitter Ready (active low). The output provides
the TX FIFO/THR status for transmit channel B. If it is not used, leave it
unconnected.
RXRDYB#
-
18
O UART channel B Receiver Ready (active low). This output provides the
RX FIFO/RHR status for receive channel B. If it is not used, leave it
unconnected.
MODEM OR SERIAL I/O INTERFACE
TXA
5
7
RXA
4
5
RTSA#
23
33
CTSA#
25
38
DTRA#
-
34
DSRA#
-
39
CDA#
-
40
RIA#
-
41
O UART channel A Transmit Data. If it is not used, leave it unconnected.
I UART channel A Receive Data. Normal receive data input must idle at
logic 1 condition. If it is not used, tie it to VCC or pull it high via a 100k
ohm resistor.
O UART channel A Request-to-Send (active low) or general purpose out-
put. If it is not used, leave it unconnected.
I UART channel A Clear-to-Send (active low) or general purpose input.
This input should be connected to VCC when not used.
O UART channel A Data-Terminal-Ready (active low) or general purpose
output. If it is not used, leave it unconnected.
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.
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.
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.
4