PM7340 S/UNI-IMA-8
PRELIMINARY
INVERSE MULTIPLEXING OVER ATM
DATA SHEET
PMC-2001723
ISSUE 3
INVERSE MULTIPLEXING OVER ATM
UTOPIA L2 Mode the virtual PHY port must first be selected prior to the start of
the data transfer. This selection is done using the same address lines that are
used for polling in combination with the TENB pin.
Data transfers are cell based, that is, an entire cell is transferred from one PHY
device before another is selected. Polling occurs concurrently with cell transfers
to ensure maximum throughput. Data pausing is not supported in Any-PHY
mode. If the TENB is deasserted prior to a complete cell being transferred, the
cell transfer error will be triggered.
The Transmit Cell Transfer Format is shown in Figure 5 and Figure 6. Word/byte
0 is required for cell transfers to an Any-PHY slave. The address prepend is the
S/UNI-IMA-8 virtual PHY ID. The virtual PHY ID can be mapped to a TC link or to
an IMA group. Optional prepends are supported, but are ignored by the S/UNI-
IMA-8.
Inclusion of optional words is statically configurable for the interface. The optional
words are always ignored.
Figure 5
- 16-bit Transmit Cell Transfer Format
Bits 15-8
Bits 7-0
Word 0
Address Prepend
(Any-PHY
only)
Word 1
Optional Prepend
HEC/UDF
(Optional)
Word 2
H1
H3
H2
H4
Word 3
Word 4
Word 5
Word 6
PAYLOAD1
PAYLOAD3
PAYLOAD2
PAYLOAD4
•
•
•
•
•
•
Word 28
PAYLOAD47
PAYLOAD48
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
43
PMC [ PMC-SIERRA, INC ]
