XRT4500 Datasheet, PDF (15/99 Pages) Exar Corporation – MULTIPROTOCOL SERIAL NETWORK INTERFACE IC

XRT4500
MULTIPROTOCOL SERIAL NETWORK INTERFACE IC
REV. 1.0.7
PIN DESCRIPTIONS (CONT.)
áç
PIN
Signal
#
31
DCE/DTE
DTE
MODE
LOW
DCE
MODE
HIGH
TYPE FUNCTION
I DCE/DTE Mode Select:
This input pin permits the user to configure the XRT4500 to
operate in either the DCE Mode or in the DTE Mode.
Logic 0: DTE Mode Operation
When the XRT4500 is configured to operate in the “DTE” Mode,
then “Transceiver # 3” will be configured to function as a
Receiver.
Logic 1: DCE Mode Operation
When the XRT4500 is configured to operate in the “DCE” Mode,
then “Transceiver # 3” will be configured to function as a Trans-
mitter. This input pin contains an internal 20KΩ pull-up to VDD.
32
RX67D
D_DCD D_LL
O Transceiver 6/7 Digital Output Pin:
The exact function of this pin depends upon whether the
XRT4500 has been configured to operate in the DCE or DTE
Mode.
DTE Mode – Data Carrier Detect (DCD) Output Pin
When the XRT4500 is operating in the DTE Mode, this trans-
ceiver functions as a “line receiver”. This line receiver accepts
either a V.10, V.28 or V.11 line signal via the TR6A and TR6B
pins (pins 29 and 30) and converts this line signal into a CMOS
level binary data stream. This binary data stream is output via
this pin. For DTE applications, this output pin should be con-
nected to the “DCD” input pin of the “Terminal Equipment”.
DCE Mode – Local Loop-back (LL) Indicator Output Pin
When the XRT4500 is operating in the DCE Mode, this trans-
ceiver functions as a “line receiver”. This line receiver accepts
either a V.10, or V.28 line signal via the TR7 input pin (pin 27)
and converts this line signal into a CMOS level binary data
stream. This binary data stream is output via this pin. For DCE
applications, this input pin should be connected to the “LL” input
pin of the “Terminal Equipment”.
NOTE: Signal names beginning with D_ are digital signals.
NOTE: Signal names ending with B and A are the positive
and negative polarities of differential signals respectively.
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