XRT4500 Datasheet, PDF (27/99 Pages) Exar Corporation – MULTIPROTOCOL SERIAL NETWORK INTERFACE IC

XRT4500
MULTIPROTOCOL SERIAL NETWORK INTERFACE IC
REV. 1.0.7
PIN DESCRIPTIONS (CONT.)
áç
PIN
Signal
#
72
GND
73
RX3D
DTE
MODE
D_TXC
DCE
MODE
D_X
TYPE FUNCTION
Analog GND: Receivers 4, 5, 6, 7 and 8
O Receiver 3 – Digital Output to Terminal Equipment:
This output pin is the digital (CMOS level) representation of the
line signal that is received via the TR3A (pin 70) and TR3B (pin
71) input pins.
The exact role that this pin plays depends upon whether the
XRT4500 is operating in the DCE or DTE Mode.
DTE Mode: TXC – Transmit Clock Signal
This output pin functions as the “TXC” (Transmit Clock) output
signal to the Terminal Equipment. The DTE Terminal Equipment
will typically use this signal to synthesize the SCTE clock signal.
DCE Mode: This output pin is NOT used.
Note: If the “Internal Oscillator” (within the XRT4500) is enabled,
then this pin will output a 32kHz to 64kHz clock signal. This clock
signal can be used for “Stand-Alone DTE Diagnostic” Testing.
74
RX2D
R_RXC D_SCTE O Receiver 2 – Digital Data Output to Equipment
This output pin is the digital (CMOS level) representation of the
line signal that is received via the RX2A (pin 77) and RX2B (pin
76) input pins.
The exact role that this pin plays depends upon whether the
XRT4500 is operating in the DCE or DTE Modes.
DCE Mode: SCTE – Transmit Clock Echo Signal:
This output pin functions as the SCTE (Transmit Clock Echo)
output signal to the Terminal Equipment. The DCE Terminal
Equipment will typically use this clock signal to sample the “TXD”
(Transmit Data).
DTE Mode: RXC – Receive Clock Signal:
This output pin functions as the “RXC” (Receive Clock) output
signal to the Terminal Equipment. The DTE Terminal Equipment
will typically use this signal to sample the “RXD” (Receive Data).
Note: If the “Internal Oscillator” (within the XRT4500) is enabled,
then this pin will output a 32kHz – 64kHz clock signal. This clock
signal can be used for “Stand-Alone DTE Diagnostic” testing.
75
EN_FLTR
I Enable Glitch Filter on Receiver 4, 5, 6, 7, 8 inputs. Internal
20kΩ pull-down
76
RX2B
RXCB SCTEB
I Receiver 2 – Positive Data Differential Input from Line
77
RX2A
RXCA RXCB
I Receiver 2 – Negative Data Differential Input from Line
24