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S/UNI-ATLAS-3200 Telecom Standard Product Data Sheet
Preliminary
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-1990553, Issue 4
398
Figure 27 POS-PHY Level 3 Ingress Logical Timing
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0000
D0
D1
D2
D14
D15
D16
D17 0001
D1
.......
......
0
0
2
0
RPP_CLK
RPP_SX
RPP_SOP
RPP_EOP
RPP_ERR
RPP_ENB
RPP_DAT[31:0]
RPP_MOD[1:0]
RPP_PAR
RPP_VAL
On the RxLink interface, the S/UNI-ATLAS-3200 will deassert RLP_RDENB to pause a
transaction if any of the per-PHY queues backs up. However, so long as S/UNI-ATLAS-3200 is
properly provisioned, and RPP_RDENB is never asserted to S/UNI-ATLAS-3200 by the switch
or TM, then this will not occur.
On the RxPHY interface, the S/UNI-ATLAS-3200 will not update its outputs when it samples
RPP_ENB deasserted.
Transferring cells over this interface is just like transferring packets. The length of the cells is
programmed into the RxPHY and RxLink blocks so that they can correctly generate and interpret
the packet, but as far as the interface is concerned, ATM cells are simply 52, 56, 60, or 64-byte
packets. There exists an option, using the ATM_FIELD and POS_FIELD bits in the RxPHY and
RxLink blocks, to insert and check an identifier in the top 8 bits of RDAT during the RLP_SX
cycle, which identifies ATM vs packet data. This feature is useful in detecting misconfigurations
in the selection of packet vs. ATM PHYs.
RxLink POS-PHY Logical Timing
In the Ingress direction, the S/UNI-ATLAS-3200 input cell/packet interface acts as a Receive
Link Layer device, and the upstream device acts as a PHY layer device, for the purposes of POS-
PHY level 3 transfers.