80KSBR200 Datasheet, PDF (17/172 Pages) Integrated Device Technology – sRIO SERIAL BUFFER FLOW-CONTROL DEVICE

IDT 80KSBR200
Notes
Advanced Datasheet*
Annex I: Software/System Bring Up Specification
Already comply.
Approved Showings
The following documents are approved showings in the TWG. Each of them will be discussed in detail.
04-11-00031.001
Change to the spec of the Serial RapidIO Receiver Sinusoidal Jitter Tolerance Mask. IDT SerDes is tuned to this spec.
3.2.2 Summation of RIO registers
The SerB shall include all registers required by the RIO spec for configuration.
3.2.3 sRIO Priorities
sRIO has two forms of priority. The first is the Standard sRIO priority. The second is the Virtual Channel form of sRIO.
There is a bit set in the data stream where VC = 0 designates standard sRIO priorities, while VC = 1 designates virtual
channels. The SerB shall not use virtual channels, but pass any virtual channel data as if it were sent with standard priority.
Standard sRIO has four discrete levels of priority (two bits). Added to the priority is the CRF (Critical Request Flow) bit
which is a priority distinguishing bit within a priority (LSB), bringing the total number of priority bits to three. High priority
packets are always sent before lower priority packets. Low priority packets do not enter the data stream until the high
priority packets are exhausted. The SerB ignores the CRF bit.
In virtual channel prioritization, there are three bits that designate the virtual channel. These replace the sRIO two bit
priority plus CRF bit. With virtual channels, each channel is allocated a percentage of the total bandwidth. In this applica-
tion, all channels are allocated some bandwidth regardless of their priority, preventing high priority packets from stealing
the entire bandwidth. The SerB shall not support Virtual Channels, but instead will always transmit higher priority packets
first.
The sRIO user may transmit data on any priority with little regard to volume of data. For instance if there operating at
close to full bandwidth with critical data, but would like to support additional service on an "as bandwidth available" basis,
he may be running with most traffic on the higher priorities and limited capacity on low priorities.
The response packet sent in most applications is intended to be sent at one priority level higher than the received
packet, which would limit the usage of the top priority to response packets, but it is not guaranteed that the user would not
use the highest priority for other data.
3.3 sRIO Simplified Overview
The operation of the sRIO bus is contained in the sRIO specification. The following comments are provided to provide a
superficial understanding of the initialization of the interface, without researching the specifications.
3.3.1 sRIO Sync
The sRIO sync is accomplished by the transmitter sending continuous /K28.5/ codes (commas) on each lane until sync
is accomplished. The state machine is shown on page VI-58 of the Physical Layer x1/x4 LP-Serial Specification for
RapidIO. The sync is tolerant of occasional /INVALID/ code groups as shown in the state machine and will increase or
decrease level of sync, based upon the error level of the interface. Upon completion of sync, each serial lane should be
able to successfully transmit and receive 8B/10B codes.
3.3.2 sRIO Alignment
After sync, the lane alignment must be completed. This is accomplished by sending continuous /A/s on all lanes. The /
A/s are counted until lane alignment is accomplished. The state machine for the "A" counters is shown on page VI-60 of
the LP-Serial Specification for RapidIO. The state machine is tolerant of an occasional /INVALID/ code group, and will
increase or decrease the state of alignment (NOT_ALIGNED to ALIGNED_3) based upon the successful transfer of /A/'s
on the lanes. A fully successful alignment would enable the 4x mode of sRIO. If links are broken and/or alignment is not
possible, the interface will be required to operate with a single link (lane 0 or 2).
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March 19, 2007
„2005 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.