XRT79L71_07 Datasheet, PDF (45/109 Pages) Exar Corporation – 1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC - HARDWARE

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PIN #
C6
NAME
RxPFrame/
RxOHInd
XRT79L71
1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC - HARDWARE
TYPE
O
DESCRIPTION
Receive PLCP Frame Indicator/Receive Overhead Indicator Output:
The function of this output pin depends upon whether the XRT79L71 has been
configured to operate in the ATM/PLCP, the Clear-Channel Framer/Serial or the
Clear-Channel Framer/Nibble-Parallel Modes.
ATM/PLCP Mode - RxPFrame - Receive PLCP Frame Indicator Output:
This output pin pulses "High" when the Receive PLCP Processor is receiving
the last bit of a PLCP frame.
NOTE: This output pin is inactive if the XRT79L71 is configured to operate in the
Direct-Mapped ATM Mode.
Clear-Channel Framer/Serial Mode - RxOHInd RxOHInd - Receive Over-
head Indicator Output:
This output pin pulses "High" for one bit-period whenever an overhead bit is
being output via the RxSer output pin, by the Receive Payload Data Output
Interface block.
NOTE: If the user configures the Receive Payload Data Output Interface block
to operate in the Gapped-Clock Mode, then this output pin will provide a
demand clock to the System-Side terminal equipment In the Gapped-
Clock Mode, this output pin will only provide a clock pulse, whenever a
payload bit is being output via the RxSer output pin. This output pin will
NOT generate a clock pulse, whenever an overhead is being output via
the RxSer output pin.
Clear-Channel Framer/Nibble-Parallel - RxOHInd RxOHInd - Receive Over-
head Indicator Output:
This output pin pulse "High" for one nibble-period whenever an overhead nibble
is being output via the RxNib[3:0] output pins by the Receive Payload Data Out-
put Interface block.
NOTES:
1. 1.If the XRT79L71 has been configured to operate in both the DS3 and
the Nibble-Parallel Modes, then the RxOHInd output pin will be in-
active and will pulled "Low" at all times.
2. If the XRT79L71 has been configured to operate in both the E3 and
the Nibble-Parallel Mode, then the RxOHInd output pin will be active
and will pulse "High" to denote overhead nibbles.
3. The purpose of this output pin is to alert the System-Side terminal
equipment that an overhead bit (or nibble) is being output via the
RxSer or RxNib[3:0] output pins and that this data should be ignored.
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