XR16M2551 Datasheet, PDF (5/51 Pages) Exar Corporation – HIGH PERFORMANCE LOW VOLTAGE DUART WITH 16-BYTE FIFO AND POWERSAVE FEATURE

XR16M2551
REV. 1.0.2
HIGH PERFORMANCE LOW VOLTAGE DUART WITH 16-BYTE FIFO AND POWERSAVE FEATURE
Pin Description
NAME
OP2A#
TXB
RXB
RTSB#
CTSB#
DTRB#
DSRB#
CDB#
RIB#
OP2B#
32-QFN 48-TQFP
TYPE
PIN # PIN #
DESCRIPTION
-
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 LOW
when MCR[3] is set to HIGH. INTA is set to the three state mode and OP2A# out-
put HIGH when MCR[3] is set to LOW. See MCR[3]. If INTA is used, this output
should not be used as a general output else it will disturb the INTA output function-
ality.
6
8
O _{UART channel B 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.
3
4
I _{UART channel B 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 in to the decoder, see MCR[6]. If this pin is
not used, tie it to VCC or pull it high via a 100k ohm resistor.
15
22
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], and
IER[6].
16
23
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 con-
nected to VCC when not used.
-
35
O _{UART channel B Data-Terminal-Ready (active low) or general purpose output. If it}
is not used, leave it unconnected.
-
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.
-
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.
-
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.
-
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 LOW
when MCR[3] is set to HIGH. INTB is set to the three state mode and OP2B# out-
put HIGH when MCR[3] is set to LOW. See MCR[3]. If INTB is used, this output
should not be used as a general output else it will disturb the INTB output function-
ality.
ANCILLARY SIGNALS
XTAL1
10
13
XTAL2
11
14
I _{Crystal or external clock input.}
O _{Crystal or buffered clock output.}
PwrSave 9
12
I PowerSave (active high). This feature isolates the M2551’s data bus interface from
the host preventing other bus activities that cause higher power drain during sleep
mode. See Sleep Mode with Auto Wake-up and PowerSave Feature section for
details.
5