XRT4500
MULTIPROTOCOL SERIAL NETWORK INTERFACE IC
REV. 1.0.7
á
8
PIN DESCRIPTIONS (CONT.)
N
OTE
:
Signal names beginning with D_ are digital signals.
N
OTE
:
Signal names ending with B and A are the positive
and negative polarities of differential signals respectively.
PIN
#
Signal
DTE
MODE
DCE
MODE
TYPE
FUNCTION
18
LP
I
Loopback Command Input Pin – Active Low:
This active-low input pin permits the user to configure the
XRT4500 into a “Loop-Back” Mode. The exact loop-back will
depend upon whether the XRT4500 is operating in the DTE or
DCE Modes.
Setting this input pin to “LOW” enables the Loop-back Operation.
Setting this input pin to “HIGH” disables the Loop-back Operation.
This input pin contains an Internal 20K
pull-up to VDD.
19
TX8O
RLA
RIA
O
Transmitter 8 – Single Ended Data Output to Line
The XRT4500 accepts a TTL level binary data stream, from the
local terminal equipment via the “TX8D” input pin (pin 17), and
outputs it, in either a V.10 or V.28 manner via this output pin. The
exact role that this output pin plays depends upon whether the
XRT4500 is operating in the DTE or DCE Modes.
If the XRT4500 is configured to operate in the DCE Mode:
This output pin will typically drive the state of either the “RI”
(Ring Indicator) or “TM” (Test Mode) signals to the Remote
Terminal Equipment.
If the XRT4500 is configured to operate in the DTE Mode:
This output pin will typically drive the state of the “RL” (Remote
Loop-back) signal to the Remote Terminal Equipment.
20
VDD
Analog VDD –
For Receivers 4, 5, 6, 7 and 8.
21
CPP
Charge Pump Capacitor Pin:
A 2.2μF tantalum capacitor must
be connected between pin 21 and pin 22.
22
CPM
Charge Pump Capacitor Pin:
A 2.2μF tantalum capacitor must
be connected between pin 21 and pin 22.