XR16C2852
2.97V TO 5.5V DUAL UART WITH 128-BYTE FIFOS
Pin Description
N
AME
RXA
44-PLCC
P
IN
#
39
T
YPE
I
D
ESCRIPTION
xr
REV. 2.1.1
UART channel A Receive Data or infrared receive data. Normal receive data input
must idleHIGH. 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.
UART channel A Request-to-Send (active low) or general purpose output. This output
must be asserted (LOW) 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.
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 connected to
VCC when not used.
UART channel A Data-Terminal-Ready (active low) or general purpose output. If this
output is not used, leave it unconnected.
UART channel A Data-Set-Ready (active low) or general purpose input. This input
should be connected to VCC when not used.
UART channel A Carrier-Detect (active low) or general purpose input. This input
should be connected to VCC when not used.
UART channel A Ring-Indicator (active low) or general purpose input. This input
should be connected to VCC when not used.
Multi-Function Output Channel A. This output pin can function as the OP2A#, BAUD-
OUTA#, or RXRDYA# 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) OP2A# - When OP2A# (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) BAUDOUTA# - When BAUDOUTA# function is selected, the 16X Baud rate clock
output is available at this pin.
3) RXRDYA# - RXRDYA# (active low) is intended for monitoring DMA data transfers.
See
for more details.
If this output is not used, leave it unconnected.
RTSA#
36
O
CTSA#
40
I
DTRA#
DSRA#
CDA#
RIA#
MFA#
37
41
42
43
35
O
I
I
I
O
TXB
26
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 this output is not used, leave it uncon-
nected.
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.
RXB
25
I
4
EXAR [ EXAR CORPORATION ]
