DS3163 Maxim Integrated Products, DS3163 Datasheet - Page 114

• Manufacturer Part Number: DS3163
• Description: IC TRPL ATM/PACKET PHY 400-PBGA
• Manufacturer: Maxim Integrated Products

Specifications of DS3163

• Applications: *
• Mounting Type: Surface Mount
• Package / Case: 400-BGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

DS3161/DS3162/DS3163/DS3164
10.5.1.4 Diagnostic Loopback (DLB)
Diagnostic loopback is enabled by setting PORT.CR4.LBM[2:0] = 1XX. DLB and LLB are enabled at the same time
when LBM[2:0] = 110, only DLB is enabled when LBM[2:0] = 10X or 111.
The Diagnostic loopback sends the transmit data, before line encoding, back to the receive side.
Transmit AIS can still be enabled using PORT.CR1.LAIS[2:0] even when DLB is enabled.
Refer to
Figure
10-9.
10.5.1.5 System Loopback (SLB)
System loopback is enabled by setting the PORT.CR4.SLB bit. The system loopback sends the packets or cells
from the transmit UTOPIA or POS-PHY interface back to the receive UTOPIA or POS-PHY interface. Cells and
packets from the line interface will be discarded.
Refer to
Figure
10-9.
10.5.2 Loss Of Signal Propagation
The Loss Of Signal (LOS) is detected in the line decoder logic if the device is set for HDB3 or B3ZS line encoding.
In unipolar (UNI) line interface modes and AMI modes LOS detection is disabled. The LOS signal from the line
decoder is sent to the DS3/E3 framer and the top level payload AIS logic except when DLB is activated. When DLB
is activated the LOS signal to the framer and AIS logic is never active. The LOS status in the line decoder status
register is valid in all frame and loop back modes, though it is always off in the line interface is in the UNI mode.
10.5.3 AIS Logic
There is AIS logic in both the framers and at the top level logic of the ports. The framer AIS is enabled by setting
the TAIS bit in the appropriate framer transmit control register (T3, E3-G.751, E3-G.832, or Clear Channel). The
top level AIS is enabled by setting the PORT.CR1.LAIS[2:0] bits (see
Table
10-16). The AIS signal is an unframed
all ones pattern or a DS3 framed 101010… pattern depending on the FM[5:0] mode bits. The DS3 Framed Alarm
Indication Signal (AIS) is a DS3 signal with valid F-bits, M-bits, and P-bits (P
and P
). The X-bits (X
and X
) are
1
2
1
2
set to one, all C-bits (C
) are set to zero, and the payload bits are set to a 1010 pattern starting with a one
XY
immediately after each overhead bit. The DS3 framed AIS pattern is only available in DS3 modes. The unframed
all ones pattern is available in all framing and clear-channel modes including the DS3 modes. The transmit line
interface can send both unframed all ones AIS and DS3 framed AIS patterns from either the AIS generator in the
framer or the AIS generator at the top level.
The AIS signal generated in the framer can be initiated and terminated without introducing any errors in the signal.
When the unframed AIS signal is initiated or terminated, there will be no BPV or CV errors introduced, there will be
framing errors if a framed mode is enabled. When the DS3 framed AIS signal is initiated or terminated, in addition
to no BPV or CV errors, there should be no framing or P-bit (parity) or CP-bit errors introduced.
The AIS signal generated at the top level will not generate BPV errors but may generate P-bit and CP-bit errors
when the signal is initiated and terminated. The framed DS3 AIS signal will not cause the far end receiver to re-
sync when the signal is initiated, but it may cause a re-sync when terminated if the DS3 frame position in the
framer is changed while the DS3 AIS signal is being generated. A sequence of events can be executed which will
enable the initiation and termination of DS3 AIS or unframed all ones at the top level without any errors introduced.
The sequence will only work when the automatic AIS generation is not enabled. CV and P-bit errors can occur
when AIS is automatically generated and cannot be avoided. This sequence to generate an error free DS# AIS at
the top level is to have the DS3 AIS or unframed all ones signal initiate in the DS3 framer, and a few frames sent
before initiating or terminating the DS3 AIS or unframed all ones at the top level. After the top level AIS signal is
activated, the AIS signal in the framer can be terminated, DLB activated and diagnostic patterns generated. The
DS3 AIS signal generated at the top level will not change frame alignment after starting even if the DS3 frame
position in the framer is changed.
The transmit line AIS generator at the top level can generate AIS signals even when the framer is looped back
using DLB, but not when the line is looped back using LLB. The AIS signal generated in the framer will be looped
back to the receive side when DLB is activated.