XR16C2850IJ-F Datasheet, PDF (5/51 Pages) Exar Corporation – 2.97V TO 5.5V DUAL UART WITH 128-BYTE FIFOS

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REV. 2.1.3
XR16C2850
2.97V TO 5.5V DUAL UART WITH 128-BYTE FIFOS
NAME
RXB
RTSB#
CTSB#
DTRB#
DSRB#
CDB#
RIB#
OP2B#
44-PLCC
PIN #
10
27
28
38
25
21
26
15
48-TQFP
PIN #
4
22
23
35
20
16
21
9
TYPE
DESCRIPTION
I _{UART channel B Receive Data or infrared receive data. Normal receive}
data input must idle HIGH. The infrared receiver pulses typically idles
LOW but can be inverted by software control prior going in to the
decoder, see MCR[6] and FCTR[2]. If this pin 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. This port must be asserted prior to using auto RTS flow control,
see EFR[6], MCR[1], FCTR[1:0], EMSR[5:4] and IER[6]. For auto
RS485 half-duplex direction control, see FCTR[3] and EMSR[3]. If this
output is not used, leave it unconnected.
I _{UART channel B Clear-to-Send (active low) or general purpose input.}
It can be used for auto CTS flow control, see EFR[7], and IER[7]. This
input should be connected to VCC when not used.
O _{UART channel B Data-Terminal-Ready (active low) or general purpose}
output. If this output 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 is LOW when MCR[3] is set to a logic 1. INTB is set
to the three state mode and OP2B# is HIGH when MCR[3] is set to a
logic 0. See MCR[3]. This output can only be used as a general pur-
pose output when interrupts are not used, otherwise it will disturb the
INTB output functionality. If this output is not used, leave it uncon-
nected.
ANCILLARY SIGNALS
XTAL1
18
13
XTAL2
19
14
HDCNTL#
-
37
I Crystal or external clock input.
O Crystal or buffered clock output.
I RS-485 half duplex directional control for channel A and B (active low).
Connect to VCC for normal RTS# function and connect to GND for RS-
485 half duplex direction control. RTS# pin goes LOW for transmit and
HIGH for receive during RS-485 mode. This pin is wire “OR-ed” with
FCTR[3]. If this pin is connected to VCC, the function of the RTS# pin
can be controlled via FCTR[3]. If this pin is connected to GND, the
RTS# pin will always be the RS-485 half duplex direction control and
can not be controlled via FCTR[3]. See FCTR[3].
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