XRT83L30 Datasheet, PDF (49/78 Pages) Exar Corporation – SINGLE-CHANNEL T1/E1/J1 LH/SH TRANSCEIVER WITH CLOCK RECOVERY AND JITTER ATTENUATOR

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XRT83L30
ONE-CHANNEL T1/E1/J1 LH/SH TRANSCEIVER WITH CLOCK RECOVERY AND JITTER ATTENUATOR
PRELIMINARY
REV. P1.3.0
REGISTER ADDRESS
00001
BIT #
D7
TABLE 19: MICROPROCESSOR REGISTER #1 BIT DESCRIPTION
NAME
RXTSEL
FUNCTION
REGISTER RESET
TYPE VALUE
Receiver Termination Select: In Host mode, this bit is used to R/W
0
select between the internal and external line termination modes
for the receiver according to the following table:
RXTSEL
0
1
RX Termination
External
Internal
D6
TXTSEL Transmit Termination Select: In Host mode, this bit is used to R/W
0
select between the internal and external line termination modes
for the transmitter according to the following table:
TXTSEL
0
1
TX Termination
External
Internal
D5
TERSEL1 Termination Impedance Select bit 1:
R/W
0
In the Host mode and in the internal termination mode (TXT-
SEL=”1” and RXTSEL=”1”), TERSEL[1:0] control the transmit
and receive termination impedance according to the following
table:
TERSEL1 TERSEL0 Termination
0
0
100Ω
0
1
110Ω
1
0
75Ω
1
1
120Ω
In the internal termination mode, the receiver termination of each
receiver is realized completely by internal resistors or by the
combination of internal and one fixed resistor (see description for
RXRES[1:0] bits).
In the internal termination mode, the transmitter output should be
AC coupled to the transformer.
D4
TERSEL0 Termination Impedance Select bit 0:
See description of bit D5 for the function of this bit.
R/W
0
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