PM6341 E1XC
DATA SHEET
PMC-910419
ISSUE 8
E1 FRAMER/TRANSCEIVER
9
FUNCTIONAL DESCRIPTION
Digital Receive Interface (DRIF)
9.1
The Digital Receive Interface provides control over the various input options
available on the multifunctional digital receive pins RDP/RDD/SDP and
RDN/RLCV/SDN. When configured for dual-rail input, the multifunctional pins
become the RDP and RDN inputs. These inputs can be enabled to receive either
return-to-zero (RZ) or non-return-to-zero (NRZ) signals; the NRZ input signals
can be sampled on either the rising or falling edge of RCLKI. When the interface
is configured for single-rail input, the multifunctional pins become the RDD and
RLCV inputs, which can be sampled on either the rising or falling RCLKI edge.
Finally, when the analog interface is used, the multifunction pins become the
SDP and SDN outputs, indicating the sliced pulses corresponding to the received
positive and negative analog line pulses.
9.2
Analog Pulse Slicer (RSLC)
The Analog E1 Pulse Slicer function is provided by the RSLC block.The Receive
Data Slicer (RSLC) block provides the first stage of signal conditioning for a
G.703 2048 kbit/s serial data stream by converting bipolar line signals to dual rail
RZ pulses. Before an RZ output pulse is generated by the RSLC block, bipolar
input signals must rise to 50% (for G.703 2048 kbit/s) of their peak amplitude.
This level is referred to as the Slicing Level. The threshold criteria insures
accurate pulse or mark recognition in the presence of noise.
The RSLC block provides a squelch alarm, which occurs when input pulses are
below the squelching level threshold. In this state, data is not sliced, which
prevents the detection of noise on an idle transmission line. The SQ status bit in
register 5DH goes high whenever the RSLC block is squelching the input signal.
The RSLC can be configured (in register 5DH) to generate an interrupt whenever
the SQ status bit goes high.
The RSLC block relies on an external network for compliance to G.703 120 Ω
twisted pair or G.703 75 Ω coax. The RSLC block is configured via an off-chip
attenuator pad (see Figure 5). The following network values are recommended
for the two intended applications:
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
39
PMC [ PMC-SIERRA, INC ]
