XRT7302IQ80 View Datasheet(PDF) - Exar Corporation
Part Name
Description
MFG CO.
'XRT7302IQ80' PDF : 77 Pages View PDF
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2 CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT
XRT7302
REV. 1.1.0
FIGURE 11. AN EXAMPLE OF HDB3 ENCODING
Data 1 0 1 1 0 0 0 0 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 0 0
001
TPData
TNData
TxClk
Line
00 0 V
B 00 V
2.3.3 Disabling the "HDB3/B3ZS" Encoder
The XRT7302 device permits the user to disable the
"HDB3/B3ZS" Encoder by two means.
When the XRT7302 Device is operating in the
"Host" Mode.
Configuring Channel 1
When the XRT7302 Device is operating in the
"Hardware" Mode.
The "HBD3/B3ZS Encoder" blocks (within both chan-
nels) are disabled by setting the "ENDECDIS (Encod-
er/Decoder Disable)" input pin (pin 17) to "0".
NOTE: By executing this step, the user will globally disable
the "HDB3/B3ZS" Encoder and Decoder blocks within each
channel of the XRT7302 device.
When the XRT7302 device is operating in the "Host"
Mode, then the "HDB3/B3ZS" Encoders (within each
channel) can be individually enabled or disabled.
The user can disable the "HDB3/B3ZS Encoder"
block within Channel 1 by setting the "ENDECDIS1"
bit-field, within Command Register (CR2), to "1" as il-
lustrated below.
COMMAND REGISTER, CR2 (ADDRESS = 0X02)
D4
D3
D2
D1
D0
Reserved
X
ENDECDIS1
1
ALOSDIS1
X
DLOSDIS1
X
REQEN1
X
Configuring Channel 2
Likewise, the user can disable the "HDB3/B3ZS En-
coder" block within Channel 2 by writing a "1" into the
"ENDECDIS2" bit-field within Command Register
CR10, as illustrated below.
COMMAND REGISTER, CR10 (ADDRESS = 0X0A)
D4
D3
D2
D1
D0
Reserved
X
ENDECDIS2
1
ALOSDIS2
X
DLOSDIS2
X
REQEN2
X
NOTE: Note: This method can only be used if the XRT7302
device is operating in the "Host" Mode.
If the user employs either of these two methods to
disable the "HDB3/B3ZS" Encoder, then the LIU will
be transmitting the data, onto the line, as it is received
via the TPData and TNData input pins.
2.4 THE TRANSMIT PULSE SHAPING CIRCUITRY
The Transmit Pulse Shaper Circuitry consists of a
Transmit Line Build-Out circuit which can be enabled
or disabled, by setting the TxLEV input pin (or "Tx-
LEV" bit-field) to "HIGH" or "LOW". The purpose of
the "Transmit Line Build-Out" circuit is to permit the
user to configure each channel within the XRT7302
device to transmit an output pulse which is compliant
to either of the following pulse template requirements
(when measured at the Digital Cross Connect Sys-
33
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