XR16C2852_05 Datasheet, PDF (5/51 Pages) Exar Corporation – 2.97V TO 5.5V DUAL UART WITH 128-BYTE FIFOS

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REV. 2.1.1
Pin Description
NAME
RTSB#
44-PLCC
PIN #
23
CTSB#
28
DTRB#
27
DSRB#
29
CDB#
30
RIB#
31
MFB#
19
XR16C2852
2.97V TO 5.5V DUAL UART WITH 128-BYTE FIFOS
TYPE
DESCRIPTION
O UART channel B Request-to-Send (active low) or general purpose output. 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]. 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.
I _{UART channel B Carrier-Detect (active low) or general purpose input. This input}
should be connected to VCC when not used.
I _{UART channel B Ring-Indicator (active low) or general purpose input. This input}
should be connected to VCC when not used.
O Multi-Function Output Channel B. This output pin can function as the OP2B#, BAUD-
OUTB#, or RXRDYB# pin. One of these output signal functions can be selected by
the user programmable bits 1-2 of the Alternate Function Register (AFR). These sig-
nal functions are described as follows:
1) OP2B# - When OP2B# (active low) is selected, the MF# pin is LOW when MCR bit-
3 is set to a logic 1 (see MCR bit-3). MCR bit-3 defaults to a logic 0 condition after a
reset or power-up.
2) BAUDOUTB# - When BAUDOUTB# function is selected, the 16X Baud rate clock
output is available at this pin.
3) RXRDYB# - RXRDYB# (active low) is intended for monitoring DMA data transfers.
See Table 2 on page 9 for more details.
ANCILLARY SIGNALS
XTAL1
11
XTAL2
13
RESET
21
VCC
GND
44, 33
22, 12
If this output is not used, leave it unconnected.
I Crystal or external clock input.
O Crystal or buffered clock output.
I Reset (active high) - A longer than 40 ns HIGH pulse on this pin will reset the internal
registers and all outputs. The UART transmitter output will be held HIGH, the receiver
input will be ignored and outputs are reset during reset period (see Table 16 on
page 38).
Pwr 2.97V to 5.5V power supply. All inputs are 5V tolerant for devices with top mark date
code of "F2 YYWW" and newer.
Pwr Power supply common, ground.
NOTE: Pin type: I=Input, O=Output, I/O= Input/output, OD=Output Open Drain.
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