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RELEASED
PM73122 AAL1GATOR-32
DATASHEET
PMC-1981419
ISSUE 7
32 LINK CES/DBCES AAL1 SAR PROCESSOR
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
178
The EXSBI is responsible for extracting links from the SBI Drop bus and
switching them to either SPE#1 which is mapped to the lower 16 links or SPE#2
which is mapped to the upper 16 links. The links are output to an internal
parallel bus.
The INSBI is responsible for taking links from the internal parallel bus and
inserting the remapped links to the SBI Add bus.
The PISO block is responsible for taking the internal parallel bus from EXSBI and
serializing the links for the local link interface. It is also responsible for
generating the receive serial clocks for the local links going to each A1SP block.
There is one PISO block for each group of 16 links.
The SIPO block is responsible for taking the serial links from the local link
interface and putting them onto the internal parallel bus to INSBI. It is also
responsible for handling the generation of the transmit serial clock for the local
links coming from the A1SP blocks, if the local link is receiving its transmit timing
from the SBI. There is one SIPO block for each group of 16 links.
11.6.3.1.9.1 Parallel In to Serial Out Converter (PISO)
The Parallel In to Serial Out Converter (PISO) serializes up to 16 T1, E1 links or
1 DS3 link which have been demapped from the SBI. The mode of this block is
determined by LINK_TYPH and LINK_TYPL in SBI_LNK_CFG_REG. The
SER_ENBL bit in each Extract Tributary Control Register enables the
corresponding link within the PISO block. This block also performs the
desynchronizer function to provide a low jitter T1, E1 serial clock and data for the
A1SP blocks as well as generating a frame sync or multi-frame sync pulse and
correct alignment of the signaling as the data is passed to the local links. The
PISO can also take the RL_CLK serial clock as an input clock in DS3 mode.
11.6.3.1.9.1.1
Desynchronizer
11.6.3.1.9.1.1.1
E1/T1 Clock Generation
The Desynchronizer uses a combination of two clock generation techniques to
desynchronize the demapped T1s and E1s. Incoming bit stuff events cause an
extra bit of data to be generated or removed from the generated serial stream
over the following 2KHz multi-frame. Pointer justifications are spread out by
advancing or retarding the generated T1 or E1 clock phase.
REFCLK is used to generate an internal nominal 1.544Mb/s or 2.048Mb/s clock
over the 2KHz frame as is indicated by the C1FP pin. A nominal T1 rate consists
of 772 clocks in 500us. A nominal E1 rate consists of 1024 clocks in 500us. Stuff