XR16C2550 Datasheet, PDF (4/38 Pages) Exar Corporation – 2.97V TO 5.5V DUART WITH 16-BYTE FIFO

XR16C2550
2.97V TO 5.5V DUART WITH 16-BYTE FIFO
xr
REV. 1.0.1
Pin Description
NAME
40-PDIP 44-PLCC 48-TQFP
TYPE
PIN #
PIN #
PIN #
DESCRIPTION
RXRDYB#
-
23
18
O UART channel B Receiver Ready (active low). This output provides
the RX FIFO/RHR status for receive channel B. See Table 2. If it is
not used, leave it unconnected.
MODEM OR SERIAL I/O INTERFACE
TXA
11
13
7
O UART channel A Transmit Data. If it is not used, leave it uncon-
nected.
RXA
10
11
5
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.
RTSA#
32
36
33
O UART channel A Request-to-Send (active low) or general purpose
output. If it is not used, leave it unconnected.
CTSA#
36
40
38
I UART channel A Clear-to-Send (active low) or general purpose
input. This input should be connected to VCC when not used. This
input has no effect on the UART.
DTRA#
33
37
34
O UART channel A Data-Terminal-Ready (active low) or general pur-
pose output. If it is not used, leave it unconnected.
DSRA#
37
41
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#
38
42
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#
39
43
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#
31
35
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 to a logic 0 when MCR[3] is set to a logic
1. INTA is set to the three state mode and OP2A# to a logic 1 when
MCR[3] is set to a logic 0. See MCR[3]. This output should not be
used as a general output else it will disturb the INTA output function-
ality. If it is not used at all, leave it unconnected.
TXB
12
14
8
O UART channel B Transmit Data. If it is not used, leave it uncon-
nected.
RXB
9
10
4
I UART channel B 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.
RTSB#
24
27
22
O UART channel B Request-to-Send (active low) or general purpose
output. If it is not used, leave it unconnected.
CTSB#
25
28
23
I UART channel B Clear-to-Send (active low) or general purpose
input. This input should be connected to VCC when not used. This
input has no effect on the UART.
DTRB#
34
38
35
O UART channel B Data-Terminal-Ready (active low) or general pur-
pose output. If it is not used, leave it unconnected.
4