PM5364 pmc-sierra, PM5364 Datasheet - Page 183

• Manufacturer Part Number: PM5364
• Description: Tupp 2488 Assp Telecom Standard
• Manufacturer: pmc-sierra

13.6.9
13.6.10
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2011334, Issue 7
A bias is created towards negative justifications and the FIFO depth can be reduced overall
because of the lack of internally generated justifications from plesiochronous input and output
clocks. In doing so, the FIFO tends towards a low fill level, which reduces the latency by as
much as 45%.
The SVCA_R can be configured to operate in this manner by setting the following bits in the
internal SVCA Pointer Justification Thresholds register, 09H:
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The latency of the SVCA_R using the default values for NTHRES[3:0] and PTHRES[3:0] is:
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Using the new values for NTHRES[3:0] and PTHRES[3:0] (above) the latency of the SVCA_R
is reduced to:
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PP Subsystem SVCA_R Bypass
The SVCA_R blocks within the PP Subsystem may be optionally bypassed by setting the
ISVCA_ESDIS bit of the Ingress SVCA Configuration register to a logic 1. Similarly, each
SVCA_R block can be bypassed independently from the others within the PP subsystem by
setting the ESDIS bit of the associated SVCA Miscellaneous Register to a logic 1. When
bypassed, the SVCA_R does not re-align the input data to a new transport frame alignment, the
internal FIFO is locked, and data is passed with minimal delay.
PP Subsystem Modes of Operation
The Payload Processor Subsystem supports seven modes of operation. Some modes can be
simultaneously supported at an STS-1/STM-0 or STS-3/STM-1 granularity. Others are only
supported individually at an STS-12/STM-4 or STS48/STM-16 (with four payload processors)
granularity. The modes are:
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NTHRES[3:0] = “1111”
PTHRES[3:0] = “0011”
Minimum latency = 1.18 µs
Typical latency = 2.25 µs
Maximum latency = 3.30 µs
Minimum latency = 0.53 µs
Typical latency = 1.19 µs
Maximum latency = 1.825 µs
Tributary Mode
Bypass STS-1 Mode
AU4 to AU3 Tributary Mode
AU4 to AU3 Bypass Mode
AU3 to AU4 Tributary Mode 1
TUPP™ 2488 ASSP Telecom Standard Product Data Sheet
Released
183