XRT4500 Datasheet, PDF (20/99 Pages) Exar Corporation – MULTIPROTOCOL SERIAL NETWORK INTERFACE IC

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PIN DESCRIPTIONS (CONT.)
XRT4500
MULTIPROTOCOL SERIAL NETWORK INTERFACE IC
REV. 1.0.7
PIN
Signal
#
50
2CK/3CK
DTE
MODE
DCE
MODE
TYPE FUNCTION
I 2 or 3 Clock Select Input Pin
This input pin permits the XRT4500 to operate in either the “2
Clock” or “3 Clock” Mode. If the XRT4500 is configured to oper-
ate in the ‘2-Clock’ mode, then the XRT4500 will synthesize the
‘RX2D’ Clock signal, from the clock signal applied at the ‘TX3D’
input pin. Conversely, if the XRT4500 is configured to operate in
the ‘3 Clock’ Mode, then the XRT4500 will synthesize the ‘RX2D’
Clock signal from the live signal received via ‘RX2A’ and ‘RX2B’
input pin. Setting this input pin “high” configures the XRT4500 to
operate in the “2 Clock” Mode. Conversely, setting this input pin
“low” configures the XRT4500 to operate in the “3 Clock” Mode.
Note:
1. This input pin is ignored if the XRT4500 is configured to
support the X.21 Communications Interface.
Logic Don’t Care: 1 Clock When in the X.21 Mode (M2, M1, M0 = 011)
Logic 0: 3 Clocks When Mode ≠ X.21 (M2, M1, M0 ≠ 011)
Logic 1: 2 Clocks When Mode ≠ X.21 (M2, M1, M0 ≠ 011)
51 VDD_REG
52
SR_OUT
NOTE:
2. This input pin is ignored if the XRT4500 is configured to
operate in the DTE Mode.
This input pin contains an internal 20kΩ pull-up to V_DD.
Analog VDD – Charge pump and switching regulator output
drivers
O Switching Regulator – Inductor driver output
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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