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March 31, 2008

IDT80KSW0004

Datasheet

4 Device Description

The CPS-12 is optimized for DSP cluster applications at board level. Its main function is to have a backplane interface which can connect to a back-

plane switch or directly to multiple RF cards. On the line card side it can also connect to multiple ports. It supports up to 12 ports which are config-

urable as line card, or backplane ports. It is an end-point free (switch) device in an sRIO network.

The CPS-12 receives packets from up to 12 ports. The CPS offers full support for normal switching as well as enhanced functions:

1) Normal Switching: All packets are switched in accordance with standard serial RapidIO specifications, with packet destination IDs determining

how the packet is routed.

Three major options exist within this category:

a.

Multicast: If a Multicast ID is received, the CPS-12 performs a multicast as defined in the sRIO multicast registers.

b. Unicast: All other operations are performed as specified in sRIO.

c. Maintenance packets: As specified by sRIO.

The sRIO Switch supports a peak throughput of 30 Gbps which is the line rate for 12 ports in 1x configuration, each at 2.5 Gbps (3.125 Gbps minus

the sRIO-defined 8b10b encoding), and switches dynamically in accordance with the packet headers and priorities.

2) Enhanced functions

Enhanced features are provided for support of system debug. These features which are optional for the user consist of two major functions:

a. Packet Trace: The Packet Trace feature provides at-speed checking of the first 160 bits (header plus a portion of any payload) of every

incoming packet against user-defined comparison register values. The trace feature is available on all serial RapidIO ports, each acting inde-

pendently from one another. If the trace feature is enabled for a given port, every incoming packet is checked for a match against up to 4 com-

parison registers. In the event of a match, either of two possible user defined actions may take place:

i) not only does the packet route normally through the switch to its appropriate destination port, but this same packet is replicated and sent to

a “trace port.” The trace port itself may be any of the standard serial RapidIO ports. The port used for the trace port is defined by the user

through simple register configuration.

ii) the packet is dropped.

If there is no match, the packets route normally through the switch with no action taken.

The Packet Trace feature can be used during system bring-up and prototyping to identify particular packet types of interest to the user. It

might be used in security applications, where packets must be checked for either correct or incorrect tags in either of the header or payload.

Identified (match) packets are then routed to the trace port for receipt by a host processor, which can perform an intervention at the software

level.

b. Port Loopback: The CPS-12 offers internal loopback for each port that may be used for system debug of the high speed sRIO ports. By

enabling loopback on a given port, packets sent to the port’s receiver are immediately looped back at the physical layer to the transmitter -

bypassing the higher logical or transport layers.

c. Broadcast: Each multicast mask can be configured so that the source port is included among the destination ports fo that multicast operation.

The CPS-12 can be programmed through any one or combination of sRIO, I2C, or JTAG. Note that any sRIO port may be used for programming.

The CPS-12 can also configure itself on power-up by reading directly from ROM over I2C in master mode.