XR16L2551 Datasheet, PDF (5/48 Pages) Exar Corporation – LOW VOLTAGE DUART WITH POWERSAVE

áç
REV. 1.0.0
Pin Description
NAME
32-QFN
PIN #
OP2A#
-
TXB
6
RXB
3
RTSB#
15
CTSB#
16
DTRB#
-
DSRB#
-
CDB#
-
RIB#
-
OP2B#
-
ANCILLARY SIGNALS
XTAL1
10
XTAL2
11
16/68#
17
XR16L2551
LOW VOLTAGE DUART WITH POWERSAVE
48-TQFP
PIN #
32
8
4
22
23
35
20
16
21
9
TYPE
DESCRIPTION
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. This output should not be used as a general output else it
will disturb the INTA output functionality. If it is not used at all, leave it
unconnected.
O UART channel B Transmit Data. If it is not used, leave it unconnected.
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.
O UART channel B Request-to-Send (active low) or general purpose out-
put. If it is not used, leave it unconnected.
I UART channel B Clear-to-Send (active low) or general purpose input.
This input should be connected to VCC when not used.
O UART channel B Data-Terminal-Ready (active low) or general purpose
output. If it is not used, leave it unconnected.
I UART channel B 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 B 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 B 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.
O Output Port 2 Channel B - 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. This output should not be used as a general output else it
will disturb the INTB output functionality. If it is not used, leave it uncon-
nected.
13
I Crystal or external clock input.
14
O Crystal or buffered clock output.
24
I Intel or Motorola Bus Select.
When 16/68# pin is at logic 1, 16 or Intel Mode, the device will operate
in the Intel bus type of interface.
When 16/68# pin is at logic 0, 68 or Motorola mode, the device will
operate in the Motorola bus type of interface.
5