28
x r
PRELIMINARY
E3 UNI FOR ATM
XRT7234
REV. P1.0.0
62
93
RxOHClk
O
Receive E3 Framer Overhead Bytes Serial Output Port Clock.
This pin, along with the RxOH and RxOHFrame pins function as the
“Receive E3 Framer Overhead byte” serial output port. This pin functions
as a clock signal that can be used by external circuitry to latch and process
the serial data from the RxOH pin.
94
NC
****
Not Bonded Out
63
95
RxOHFrame
O
Receive E3 Framer Overhead Byte Serial Output Port—Frame
Boundary Indicator:
This pin, along with the RxOH and RxOHClk signals
comprise the “Receive E3 Framer OH Bit” Serial Output Port. This pin
pulses high when the first overhead bit of a E3 frame (e.g., the MSB-bit
in the Frame Alignment octet: FA1) is output at the RxOH pin.
96
RxFrame
O
Receive Boundary of E3 Frame Output Indicator:
This output pin indicates
the boundary of the incoming E3 frame as they appear, at the RxPOS
and RxNEG inputs. This pin marks the end of a E3 frame by pulsing high
for one bit period at the end of each frame.
64
97
RxPOS
I
Receive Positive Data Input:
The exact role of this input pin depends
upon whether the UNI is operating in the Unipolar or Bipolar Mode.
Unipolar Mode:
This input pin functions as the “Single-Rail” input for the
“incoming” E3 data stream. The signal at this input pin will be sampled
and latched (into the Receive E3 Framer) on the “user-selected” edge of
the RxLineClk signal.
Bipolar Mode:
This input functions as one of the dual rail inputs for the
incoming AMI/HDB3 encoded E3 data that has been received from an
external Line Interface Unit (LIU) IC. RxNEG functions as the other dual
rail input for the UNI. When this input pin is asserted, it means that the
LIU has received a “positive polarity” pulse from the line.
65
98
RxNEG
I
Receive Negative Data Input:
The exact role of this input pin depends
upon whether the UNI is operating in the Unipolar or Bipolar Mode.
Unipolar Mode:
This input pin is inactive, and should be pulled (“l(fā)ow” or
“high”) when the UNI is operating in the Unipolar Mode.
Bipolar Mode:
This input pin functions as one of the dual rail inputs for
the incoming AMI/HDB3 encoded E3 data that has been received from
an external Line Interface Unit (LIU) IC. RxPOS functions as the other
dual rail input for the UNI. When this input pin is asserted, it means that
the LIU has received a “negative polarity” pulse from the line.
PIN DESCRIPTION (CONTINUED)
Pin
No.
100 Pin Package
Pin No. 160
PinPackage
Symbol
Type
Description