XRT83L30 Datasheet, PDF (54/78 Pages) Exar Corporation – SINGLE-CHANNEL T1/E1/J1 LH/SH TRANSCEIVER WITH CLOCK RECOVERY AND JITTER ATTENUATOR

XRT83L30
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ONE-CHANNEL T1/E1/J1 LH/SH TRANSCEIVER WITH CLOCK RECOVERY AND JITTER ATTENUATOR
REV. P1.3.0
PRELIMINARY
TABLE 21: MICROPROCESSOR REGISTER #3 BIT DESCRIPTION
D4
RXRES1 Receive External Resistor Control pin 1: In Host mode, this bit R/W
0
along with the RXRES0 bit selects the value of the external
Receive fixed resistor according to the following table:
RXRES1 RXRES0
Required Fixed External
RX Resistor
0
0
No External Fixed Resistor
0
1
60Ω
1
0
52.5Ω
1
1
37.5Ω
D3
RXRES0 Receive External Resistor Control bit 0: For function of this bit R/W
0
see description of D4 the RXRES1 bit.
D2
INSBPV Insert Bipolar Violation: When this bit transitions from "0" to
R/W
0
"1", a bipolar violation is inserted in the transmitted data stream.
Bipolar violation can be inserted either in the QRSS pattern, or
input data when operating in single-rail mode. The state of this bit
is sampled on the rising edge of TCLK.
NOTE: To ensure the insertion of a bipolar violation, a "0" should
be written in this bit location before writing a "1".
D1
Reserved
R/W
0
D0
TRATIO Transformer Ratio Select: In the external termination mode,
R/W
0
writing a “1” to this bit selects a transformer ratio of 1:2 for the
transmitter. Writing a “0” sets the transmitter transformer ratio to
1: 2.45. In the internal termination mode the transmitter trans-
former ratio is permanently set to 1:2 and the state of this bit has
no effect.
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