CX28344 Conexant, CX28344 Datasheet - Page 91

• Manufacturer Part Number: CX28344
• Description: (CX2834x) Dual / Triple / Quad / Hex / Octal - Enhanced DS3 / E3 Framer
• Manufacturer: Conexant

CX28342/3/4/6/8 Data Sheet
2.2.5.1
2.2.5.2
2.2.5.3
28348-DSH-001-B
Bipolar Violation (BPV), Excessive Zeros (EXZ), and Line Code Violation (LCV)
A BPV is defined as the occurrence of a signal of same polarity as the previous one in
an AMI mode or rail mode pulse sequence. An EXZ is defined as the occurrence in
rail mode of more than two DS3 or three E3 consecutive 0s, regardless of the length of
the zero string.
A LCV is defined as the occurrence of either EXZ or BPV , excluding those that are
part of the zero substitution code in DS3 mode. In E3 mode, the LCV is defined as the
occurrence of two consecutive BPVs of the same polarity.
In rail mode (B3ZS/HDB3), LCV and EXZ events are counted. In AMI mode BPV
events are used to increment the LCV counter. In unipolar mode, only LCV is valid,
and the LCV (defined as a pulse on RXNEG/LCVI pin) counter is updated.
Loss of Signal (LOS)
In DS3, LOS is declared when there are no signal pulses of either polarity over a
period of 100 contiguous pulse intervals in rail mode. The LOS event is terminated
when the pulse density equals or exceeds 33% over a period of 100 contiguous pulse
intervals. The same definition is true in AMI mode.
In E3 mode, LOS is declared when there are no signal pulses of either polarity over a
period of 100 contiguous pulse intervals in rail mode. The LOS event is terminated
when the pulse density equals or exceeds 25% over a period of 100 contiguous pulse
intervals. The same definition is true in AMI mode. In unipolar mode, LOS event is
undefined.
When a LOS is initiated, it generates a LOSStrt interrupt indication and sets the LOS
status indication bit (the LOSAlm field of the Maintenance Status register). Upon the
termination of the LOS event, the LOS event generates a LOSEnd interrupt indication
and clears the LOS status indication bit.
In the presence of LOS in the E3 and DS3 modes, if the Auto RAI field is set in the
Transmit Overhead Insertion 1 Control register, RAI/RDI is transmitted on the
transmit stream.
In the presence of LOS in the E3 and DS3 modes, if the RxAutoAll1 field is set in the
Feature5 Control register, an all-1s sequence is transmitted on RXDAT towards the
receive system side.
Framing Bit Error (FBE)
In E3, an FBE event occurs when a framing bit (FAS, F, M, or FA) in the receive
stream is different from the expected value. The FBE event increments a FBE
counter.
In DS3 C-bit parity mode, an FBE event is valid and counted. If internal FEBE
generation is programmed for the transmitter by clearing the ExtFEBE/Cj-bit in the
TransmitOverheadInsertion1 Control register, the detection of a framing bit error in
the receiver causes transmission of FEBE error code by the transmitter.
Mindspeed Technologies™
Functional Description
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