XR16V2551 Datasheet, PDF (4/51 Pages) Exar Corporation – HIGH PERFORMANCE DUART WITH 16-BYTE FIFO AND POWERSAVE FEATURE

XR16V2551
PRELIMINARY
HIGH PERFORMANCE DUART WITH 16-BYTE FIFO AND POWERSAVE FEATURE
Pin Description
REV. P1.0.0
NAME
32-QFN 48-TQFP
TYPE
PIN # PIN #
DESCRIPTION
INTB
21
29
O _{UART channel B Interrupt output. The output state is defined by the user through}
the software setting of MCR[3]. INTB is set to the active mode and OP2B# output
LOW when MCR[3] is set to a logic 1. INTB is set to the three state mode and
OP2B# output HIGH when MCR[3] is set to a logic 0 (default). See MCR[3].
TXRDYA# -
43
O _{UART channel A Transmitter Ready (active low). The output provides the TX FIFO/}
THR status for transmit channel A. See Table 3. If it is not used, leave it uncon-
nected.
RXRDYA# -
31
O _{UART channel A Receiver Ready (active low). This output provides the RX FIFO/}
RHR status for receive channel A. See Table 3. If it is not used, leave it uncon-
nected.
TXRDYB# -
6
O _{UART channel B Transmitter Ready (active low). The output provides the TX FIFO/}
THR status for transmit channel B. See Table 4. If it is not used, leave it uncon-
nected.
RXRDYB# -
18
O _{UART channel B Receiver Ready (active low). This output provides the RX FIFO/}
RHR status for receive channel B. See Table 3. If it is not used, leave it uncon-
nected.
MODEM OR SERIAL I/O INTERFACE
TXA
5
7
O _{UART channel A Transmit Data or infrared encoder data. Standard transmit and}
receive interface is enabled when MCR[6] = 0. In this mode, the TX signal will be
HIGH during reset or idle (no data). Infrared IrDA transmit and receive interface is
enabled when MCR[6] = 1. In the Infrared mode, the inactive state (no data) for the
Infrared encoder/decoder interface is LOW. If it is not used, leave it unconnected.
RXA
4
5
I _{UART channel A Receive Data or infrared receive data. Normal receive data input}
must idle HIGH. The infrared receiver pulses typically idles at LOW but can be
inverted by software control prior going into the decoder, see MCR[6]. If this pin is
not used, tie it to VCC or pull it high via a 100k ohm resistor.
RTSA#
23
33
O _{UART channel A Request-to-Send (active low) or general purpose output. This out-}
put must be asserted prior to using auto RTS flow control, see EFR[6], MCR[1],
and IER[6].
CTSA#
25
38
I _{UART channel A 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 con-
nected to VCC when not used.
DTRA#
-
34
O _{UART channel A Data-Terminal-Ready (active low) or general purpose output. If it}
is not used, leave it unconnected.
DSRA#
-
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#
-
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#
-
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.
4