![](http://datasheet.mmic.net.cn/370000/ST16C2450_datasheet_16733438/ST16C2450_4.png)
ST16C2450
2.97V TO 5.5V DUART
á
REV. 4.0.0
4
INTB
32
29
O
UART 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 (default).
MODEM OR SERIAL I/O INTERFACE
TXA
13
7
O
UART channel A Transmit Data. If it is not used, leave it unconnected.
RXA
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#
36
33
O
UART channel A Request-to-Send (active low) or general purpose out-
put. If it is not used, leave it unconnected.
CTSA#
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#
37
34
O
UART channel A Data-Terminal-Ready (active low) or general purpose
output. If it is not used, leave it unconnected.
DSRA#
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#
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#
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#
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. 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.
TXB
14
8
O
UART channel B Transmit Data. If it is not used, leave it unconnected.
RXB
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#
27
22
O
UART channel B Request-to-Send (active low) or general purpose out-
put. If it is not used, leave it unconnected.
CTSB#
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#
38
35
O
UART channel B Data-Terminal-Ready (active low) or general purpose
output. If it is not used, leave it unconnected.
Pin Description
N
AME
44-PLCC
P
IN
#
48-TQFP
P
IN
#
T
YPE
D
ESCRIPTION