S/UNI-IMA-4 Telecom Standard Product Data Sheet
Released
UTOPIA Level 2 Single-Address Slave Mode
In UTOPIA Level 2 Single Address Slave mode, the S/UNI-IMA-4 operates as a single device
with a single large 124 cell FIFO, with all cells being identified by their virtual PHY ID (VPHY
ID) in an address prepend. Each IMA or TC connection is limited to a maximum of 16 cells in
the FIFO. The address prepend may be optionally mapped to the HEC/UDF field in order to
maintain the standard cell length. When the address presented on the Any-PHY/UTOPIA
Interface RADR pins matches a programmable 5-bit configuration register (DEVID), the
RXAPS will respond to polls. In all other cases, the output signals are tristated that allows other
slave devices to respond. When polled, the RPA output indicates whether there is at least one
cell available for transfer from any link.
Any-PHY Slave Mode
In Any-PHY Slave mode, the S/UNI-IMA-4 operates as a single device with a single large 124
cell FIFO, with all cells being identified by their virtual PHY ID (VPHY ID) in an address
prepend. Each IMA or TC connection is limited to a maximum of 16 cells in the FIFO. When
the address presented on the Any-PHY/UTOPIA Interface RADR pins matches a programmable
5-bit configuration register (DEVID), the RXAPS will respond to polls. In all other cases, the
output signals are tristated that allows other slave devices to respond. When polled, the RPA
output indicates whether there is at least one cell available for transfer from any link. In Any-
PHY mode, data pausing is not supported.
To support current and future ATM Layer devices, the cell interface is configurable as either an
Any-PHY or UTOPIA L2 interface. Table 2 summarizes the distinctions between the two
protocols.
Table 2 UTOPIA L2 and Any-PHY Comparison
Attribute
Latency
UTOPIA L2
Any-PHY
RDAT[15:0], RPRTY, and RSOP are
driven or become high impedance
immediately upon sampling RENB low
or high, respectively. The RPA is
driven with the cell availability status
one CLK cycle after the RADR[4:0]
RDAT[15:0], RPRTY, RSOP and RSX
are driven or become high impedance
on the RCLK rising edge following the
one that samples RENB low or high,
respectively. The RPA is driven with
the cell availability status two CLK
pins match the S/UNI-IMA-4’s address. cycles after RADR[4:0] pins match the
A match is defined as either matching
the programmed value in single PHY
mode or being within the correct range
for multi-PHY mode.
S/UNI-IMA-4’s address.
RSX
Undefined. It is low when not high
High coincident with the first word of
the cell data structure.
impedance.
RSOP
High coincident with the first word of
the cell data structure.
High coincident with the first byte of
the cell header.
Paused transfers Permitted by deasserting RENB high,
but the S/UNI-IMA’s address must be
presented on RADR[4:0] the last cycle
RENB is high to reselect the same
PHY.
Not Permitted.
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2020889, Issue 2
48
PMC [ PMC-SIERRA, INC ]
