ST16C2450 Datasheet, PDF (5/29 Pages) Exar Corporation – 2.97V TO 5.5V DUART

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REV. 4.0.0
ST16C2450
2.97V TO 5.5V DUART
Pin Description
NAME
44-PLCC
PIN #
48-TQFP
PIN #
TYPE
DESCRIPTION
DSRB#
25
20
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.
CDB#
21
16
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.
RIB#
26
21
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.
OP2B#
15
9
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.
ANCILLARY SIGNALS
XTAL1
18
13
I Crystal or external clock input.
XTAL2
19
14
O Crystal or buffered clock output.
RESET
39
36
I Reset (active high) - A longer than 40 ns logic 1 pulse on this pin will
reset the internal registers and all outputs. The UART transmitter out-
put will be held at logic 1, the receiver input will be ignored and outputs
are reset during reset period.
VCC
44
42
Pwr 2.97V to 5.5V power supply. All inputs are 5V tolerant for devices with
top marking of "A2 YYWW" and newer.
GND
22
17
Pwr Power supply common, ground.
N.C.
1, 12, 23,
34
6, 12, 18,
24, 25, 31,
37, 43
- No Connection. These pins are open, but typically, should be con-
nected to GND for good design practice.
Pin type: I=Input, O=Output, IO= Input/output, OD=Output Open Drain.
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