70K2000 Datasheet, PDF(2/2 Page) Integrated Device Technology – Serial RapidIO Pre-Processing Switch for DSP Clusters

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IDT 70K2000

Functional Description

The Pre-Processing Switch (PPS) from IDT is optimized for DSP cluster applica-

tions at board level. Its main function is to have a backplane interface which can

connect to a backplane switch or directly to multiple RF cards. On the line card

side it can also connect to multiple ports. It supports up to 22 ports which are

configurable as line card, or backplane ports. It is an end-point free (switch)

device in an sRIO network.

If packets are addressed to a certain port or a range of addresses, the unproc-

essed data samples in their payload will be preprocessed to make them more

âDSP-friendlyâ. If not, the packets are switched as defined by the transport layer

sRIO specification. The packet manipulation in the PPS is transparent to the

sRIO protocol.

The PPS receives the packets from a total of 22 ports. Depending on the device

ID field within a received packet, two functions can be performed by the PPS:

1) Packet Processing: If DestID in the sRIO transport layer is one of

the Packet Processing Scenario (PPSc) addresses specified in the

PPSc registers, the PPS terminates the sRIO packet and implements

the sample preprocessing.

The sample preprocessing operations are defined in Packet Process-

ing Scenarios (PPSc). There are a total of 10 individual PPScs in the

PPS. There are also 8 Group PPScs (GPPSc), each of which may be

linked to 4 individual PPScs.

2) Switching: All other addresses are treated as regular sRIO destina-

tion addresses, and packets are switched accordingly.

Also three major options exist within this category:

a. Multicast:If a Multicast ID is received, the PPS 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 in sRIO.

The PPS can be programmed through a CPU or a DSP connected to one of the

sRIO ports of the device or with a CPU connected to an I2C or JTAG bus. This

option is added to allow the user to use a conventional CPU instead of a sRIO

interface.

The packets received from packet processing or switching are sent to re-trans-

mit buffers, which are 8 maximum sized packets deep. 4 levels of priority can be

assigned in sRIO packets for both sample packets and standard packets to

adjust the transmission priority.

The packets are switched depending on the priority. The switched packet priority

then is compared to sample packet priority, and the highest priority goes into the

re-transmit buffer first. Once in the re-transmit buffer, the priorities do not affect

the place in the buffer.

The Packet Processing Module can reach a peak throughput of 100Gbps, which

is the line rate for 10 ports in 4x configuration, each at 3.125Gbps. It is pro-

grammed via the PPSc registers. Re-programming each PPSc dynamically is

possible, and does not affect the operation of all other PPScs, but does incur a

pause on the affected PPSc.

The sRIO Switch can sustain a peak throughput of 10Gbps, and switches

dynamically in accordance with the packet headers.

Pre-Processing Switch in Support of Baseband Processing Board, Cellular Base Station

Can be Full-Mesh

Implementation or

Centralized Switch

Baseband Card

Bridge*

Pre-Processing

Switch

RF Card

Receiver

(Down

converter)

A/D

D/A

MAC

PHY

DSP/

CRP

1x or 4x Ports

3.125 Gbps, 2.5 Gbps,

or 1.25 Gbps

Long-haul or short-haul

DSP/

CRP

DSP/

CRP

Figure 1 Interface Overview

5686 drw 01

*The IDT70K2000 provides direct support for backplane connections using the serial RapidIO standard. The addition of an appropriate bridge allows for further

backplane flexibility, accommodating designs based on a wide range of standards such as CPRI, OBSAI, GbE, PCIe, or ASI.

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February 13, 2006

â2005 Integrated Device Technology, Inc. All rights reserved. Advanced Datasheet for informational purposes only. Product specifications subject to change without notice.NOT AN OFFER FOR SALE The information presented herein is subject to a

Non-Disclosure Agreement (NDA) and is for planning purposes only. Nothing contained in this presentation, whether verbal or written, is intended as, or shall have the effect of, a sale or an offer for sale that creates a contractual power of acceptance.