
PM5317 SPECTRA-9953 Telecom Standard Product Data Sheet
Release
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2000741, Issue 5
504
3. Similarly, when the SSLLB is enabled, PAIS characters are not consistently relayed to the
Transmit line. In this case, the SHPI can be disabled as long as the RSVCA DiagTOHAIS
(Indirect Register 02H bit 6) is set to Logic 1 to correctly assert the PAIS Telecom bus
signal throughout the TOH. Otherwise, PAIS may be incorrectly removed for a single
frame at the TSVCA.
4. When an Out of Frame Alignment (OFA) condition occurs in the R8TD, the block can
optionally set the payload to all 1s. However, the PAIS Telecombus signal is not set.
Therefore, if the SHPI is disabled, PAIS will not be relayed to the Transmit Line. Again,
enabling the SHPI prevents this condition. Alternately, an interrupt can be generated from
the R8TD and AIS can be manually inserted at the TSVCA Using the Diag_PAIS bit.
5. The R8TD also shows the H3 byte as being part of the payload when in PAIS. When the
SHPI is disabled, the payload indication signal passes through the SHPI to the TSVCA,
whose FIFO will overflow due to what it perceives as constant incoming negative pointer
justifications. Also, the TSVCA will insert PAIS due to this overflow, meaning that PAIS
will be inserted in the Transmit Line even if its insertion is not enabled in the SARC with
TPAISPRTEN. Enabling the SHPI prevents this condition as the payload signal will be
regenerated, and no “negative justifications” will be seen at the TSVCA. Alternately, the
Diag_FifoAisDis in TSVCA Indirect register 02H can disable the insertion of AIS due to
FIFO overflows/underflows.
17.13 SVCA Reconfiguration Considerations
When an SVCA (TSVCA or RSVCA) undergoes a reconfiguration, (from top-level registers or
via SVCA Normal Register 02H) there is a possibility that its indirect registers will be corrupted
and consequently that data integrity will be lost. To avoid such a situation, before the
reconfiguration, the contents of Indirect Register 02H should be read and stored, and after the
reconfigureation, the contents should be written back to Indirect Register 02H. This way, data
corruption can be avoided.
17.14 JTAG Support
The SPECTRA-9953 device supports the IEEE Boundary Scan specification as described in the
IEEE 1149.1 standards. The Test Access Port (TAP) consists of the five standard pins: TRSTB,
TCK, TMS, TDI and TDO. These are used to control the TAP controller and the boundary scan
registers. The TRSTB input is the active-low reset signal used to reset the TAP controller. TCK
is the test clock used to sample data on input, TDI and to output data on output, TDO. The TMS
input is used to direct the TAP controller through its states. The basic boundary scan
architecture is shown in .