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PRELIMINARY
XRT79L71
436
REV. P2.0.0
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
Operation of the Transmit Payload Data Input Interface Block
The Transmit Payload Data Input Interface block permits the user to configure it to operate in the following
combination of modes.
The Serial or Nibble-Parallel Interface Mode
The Loop-Timing or Local-Timing Mode
If the XRT79L71 is configured to operate in the Local-Timing Mode, then there are two additional "sub-options".
The "Frame-Master" or "Frame-Slave" Mode
With these three sets of configuration options, the Transmit Payload Data Input Interface block can be
configured to operate in any one of the following six (6) Modes.
Mode 1 - Serial/Loop-Timing Mode
Mode 2 - Serial/Local-Timing/Frame Slave Mode
Mode 3 - Serial/Local-Timing/Frame Master Mode
Mode 4 - Nibble-Parallel/Loop-Timing Mode
Mode 5 - Nibble-Parallel/Local-Timing/Frame Slave Mode
Mode 6 - Nibble-Parallel/Local-Timing/Frame Master Mode
Table 57 presents a "Quick-Look" Summary of each of these Modes
TxFrameRef
A11
I
Transmit E3 Frame Reference Input::
The XRT79L71 allows the user to configure this input pin to function as the
"Transmit E3 Frame Generation Reference" Input. If this particular configura-
tion option is invoked, the TransmitE3 Framer block (within the XRT79L71) will
initiate E3 frame generation anytime it detects a rising edge of this input pin.
NOTE:
If tthis configuration option is implemented, it is imperative that this
particular input signal is synchronous with the "TxInClk" input signal.
Failure to do so will result in the transmission of erred E3 frames to the
remote terminal equipment.
RxOutClk
B5
O
Loop-Timing Reference Clock Output Pin:
If the XRT79L71 is configured to operate in the Loop-Timing Mode, then the
Transmit Section of the XRT79L71 will be configured to use the LIU Recovered
Clock signal as its timing source. In this case, the XRT79L71 will output a
34.368MHz clock signal via this particular output pin. In this configuration, the
TxInClk signal will be inactive and will NOT be used to sample and latch the
data on the TxSer input pin. In this case, the XRT79L71 will now be configured
to sample the TxSer input pin upon the rising edge of the "RxOutClk" signal.
NOTE: This output pin will always be active, in the sense that it will always
generate a 34.368MHz clock signal (even when the XRT79L71 is NOT
configured to operate in the Loop-Timing Mode).
However, the
XRT79L71 will only use this particular clock signal to sample and latch
the data on the TxSer input pin whenever the XRT79L71 has been
configured to operate in the Loop-Timing Mode.
TABLE 56: LIST AND DESCRIPTION OF THE PINS ASSOCIATED WITH THE TRANSMIT PAYLOAD DATA INPUT INTERFACE
BLOCK
SIGNAL NAME
PIN/BALL
NUMBER
TYPE
DESCRIPTION