S/UNI-IMA-4 Telecom Standard Product Data Sheet
Released
Figure 7 8-bit Transmit Cell Transfer Format
Bits 7-0
Address Prepend
Byte 0
(Any-PHY
only)
Optional Prepend[15:8]
Optional Prepend[7:0]
Byte 1
(Optional)
Byte 2
(Optional)
H1
Byte 3
Byte 4
Byte 5
Byte 6
Byte 7*
H2
H3
H4
HEC
PAYLOAD1
Byte 8
S
S
S
PAYLOAD48
Byte 55
10.1.2 Receive Any-PHY/UTOPIA Slave (RXAPS)
In the receive direction, each S/UNI-IMA-4 transmits cells on an Any-PHY/UTOPIA L2
compatible interface operating at clock rates up to 52 MHz and supporting 16-bit and 8-bit wide
cells. The S/UNI-IMA-4 operates as a bus slave.
In all modes, an optional prepend is allowed on the bus. This prepend will always be set to zero
and has no significance to the S/UNI-IMA-4 but is provided for interoperability.
UTOPIA Level 2 Multi-Address Slave Mode
In UTOPIA Level 2 Multi-Address Slave mode, the S/UNI-IMA-4 operates as a 4 port multi-
PHY with each virtual PHY stored in its own FIFO. A 4-bit configuration register, RCAEN,
controls the response to polling the individual channels within this group of 4 ports. Setting
RCAEN[0] enables any group of four ports within the addresses 0 through 7, and RCAEN[3]
enables any group of four ports within the addresses 24 through 30. This is typically used to
allow more than one slave device to share the Receive UTOPIA master bus. When polled, the
Receive Packet Available (RPA) output indicates whether there is at least one cell available for
transfer from the polled link. Upon selection, the interface handles data pausing anywhere in the
middle of a cell transfer.
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2020889, Issue 2
47
PMC [ PMC-SIERRA, INC ]
