XRT72L13 Datasheet, PDF (37/370 Pages) Exar Corporation – M13 MULTIPLEXER/CLEAR CHANNEL DS3 FRAMER IC

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PRELIMINARY
PIN DESCRIPTIONS
PIN #
NAME
155
DS2OutClk
156
TxFrameRef
157
TxFrame
158
TxInClk
159
TxNibFrame
XRT72L13
M13 MULTIPLEXER/CLEAR CHANNEL DS3 FRAMER IC
REV. P1.0.6
TYPE
O
I
O
I
O
DESCRIPTION
Transmit DS2 Clock Output
Transmit Framer Reference Input:
This input pin functions as the "Transmit Frame Generation" reference
signal, if the XRT72L13 has been configured to operate in the "Local-
Time/Frame Slave" Mode. If the XRT72L13 has been configured to
operate in the "Local-Time/Frame-Slave" Mode, then the user's termi-
nal equipment is expected to apply a pulse (to this input pin) once
every 106.4 microseconds.
In the "Local-Time/Frame-Slave" Mode, the Transmit Section of the
XRT72L13 M13 Multiplexer/Framer IC will initiate its generation of a
new "outbound" DS3 frame, upon the rising edge of this signal.
NOTE: The user can configure the XRT72L13 M13 Multiplexer/Framer
IC to operate in the "Local Time/Frame Slave" Mode by writing "xxxx
xx01" into the "Operating Mode" Register (Address = 0x00).
Transmit End of DS3 Frame Indicator:
.The Transmit Section of the XRT72L13 will pulse this output pin
"high" (for one bit-period), when the Transmit Payload Data Input
Interface is processing the last bit of a given DS3 frame.
The purpose of this output pin is to alert the Terminal Equipment that
it needs to begin transmission of a new DS3 frame to the XRT72L13
(e.g., to permit the XRT72L13 to maintain Transmit DS3 framing align-
ment control over the Terminal Equipment).
Transmit Framer Reference Clock Input.
This input pin functions as the "Timing Reference" for the Transmit
Section of the "Clear Channel DS3 Framer" block within XRT72L13
M13 Multiplexer/Framer IC; if the device has been configured to oper-
ate in the "Local-Time" Mode. Further, if the XRT72L13 M13 Multi-
plexer/Framer IC has been configured to operate in the "Local-Time"
Mode, the "Transmit Payload Data Input Interface will sample the data
at the TxSer input pin, upon the rising edge of "TxInClk".
NOTES:
1. The user should apply a 44.736MHz clock signal to this input
pin.
2. The user can configure the XRT72L13 M13 Multiplexer/
Framer IC to operate in the "Local-Time" mode by writing
"xxxx xx01" or "xxxx xx1x" into the "Operating Mode" register
(Address = 0x00).
Transmit Frame Boundary Indicator - Nibble/Parallel Interface
This output pin pulses "high" when the last nibble of a given DS3
frame is expected at the TxNib[3:0] input pins.
The purpose of this output pin is to alert the Terminal Equipment that
it needs to begin transmission of a new DS3 frame to the XRT72L13.
NOTE: This pin is only used for “Clear-Channel Framer” applications.
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