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S/UNI-QUAD
PMC-Sierra, Inc.
PM5349 S/UNI-QUAD
DATASHEET
PMC-971239 ISSUE 6 SATURN USER NETWORK INTERFACE (155-QUAD)
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
224
During multi-PHY operation, several PHY layer devices share the TCA signal. As
a result, this signals must be tri-stated in all PHY devices which have not been
selected for polling by the ATM Layer. The value of TADR[4:0] selects the PHY
being polled for the TCA signal, and all devices not corresponding to this address
must tri-state its TCA output. This multi-PHY operation is directly supported by
the S/UNI-QUAD.
Figure 23: Multi-PHY Polling and Addressing Receive Cell Interface
RCA
RSOC
RDAT[15:0]
RPRTY
W
(n-7)
W
(n-6)
W
(n-5)
W1 W2 W3W
(n-4)
W
(n-3)
W
(n-2)
W
(n-1)
W
(n)
RFCLK
RENB
RADR[4:0]
CA(A) CA(B) CA(C) CA(B)
A B 1Fh C 1Fh B X D 1Fh E 1Fh
CA(D)
X
1Fh
Figure 67 shows an example of the multi-PHY polling and selection sequence
supported by the S/UNI-QUAD. "A", "B", "C", "D", and "E" represent any arbitrary
address values which may be occupied by the S/UNI-QUAD. The ATM Layer
device is not restricted in its polling order. The PHY associated with address "A"
indicates it does not have a cell available, but PHY "B" indicates that it does. As
a result, the ATM Layer places address "B" on RADR[4:0] the cycle before RENB
is asserted to select PHY "B" as the next cell source. In this example, PHY "C"s
status is ignored. The ATM Layer device is not constrained to select the latest
PHY polled. As soon as the cell transfer is started, the polling process may be
restarted.
During multi-PHY operation, several PHY layer devices share the RDAT[15:0],
RSOC, RPRTY, and RCA signals. As a result, these signals must be tri-stated in
all PHY devices which have not been selected for reading or polling by the ATM