S/UNI-IMA-4 Telecom Standard Product Data Sheet
Released
Register 0x208: Delay Configuration Register
Bit
15:8
7:4
Type
Function
Reserved
Min_upper_guardband
Min_lower_guardband
Default
R/W
R/W
3
3
3:0
Min_lower_guardband
This value represents the minimum lower guard band needed to be introduced in the RIPP
differential delay calculation in order to account for the RDAT write pointer jitters relative
to the RDAT read pointer. In order to make sure that no underrun will occur, the following
relationship needs to be satisfied in order to accept a link:
Distance between the observed link write pointer and the read pointer >=
min_lower_guardband.
When removing delay from a group with the ADJUST_DELAY command, PM must not
reduce the minimum delay on any link in the group below this threshold. Otherwise, LODS
underrun may occur after the operation is complete. This guardband is used during group
startup and LASR operations.
Min_upper_guardband
This value represents the minimum upper guard band needed to be introduced in the RIPP
differential delay calculation in order to account for the RDAT write pointer jitters relative
to the RDAT read pointer. In order to make sure that no overrun will occur, the following
relationship needs to be satisfied in order to accept a link:
Distance between the observed link write pointer and the read pointer +
Min_upper_guardband <= RX_DELAY_TOL.
When adding delay to a group with the ADJUST_DELAY command, PM must not increase
the maximum delay on any link in the group above RX_DELAY_TOL –
Min_upper_guardband. Otherwise, LODS overrun may occur after the operation is
complete. This guardband is used during group startup and LASR operations.
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2020889, Issue 2
181
PMC [ PMC-SIERRA, INC ]
