80KSBR200 Datasheet, PDF (22/172 Pages) Integrated Device Technology – sRIO SERIAL BUFFER FLOW-CONTROL DEVICE

IDT 80KSBR200
Notes
The transaction IDs are allocated per Figure 6.
Advanced Datasheet*
ID Range sRIO Packet Generating Entity
31-0
127-32
159-128
255-160
Queue 0 Output
Reserved for future use
Device ID of the SerB
Doorbells and reserved
Figure 6 Transaction ID Range for sRIO Packet Generating Entities
Source ID, Destination ID, and Transaction ID all are used to identify a unique packet. If this includes the transaction
type or some additional ID, the problems of multiple identical transaction types would be solved. Response packets are
identified as response packets, which identify the originator of the request, the source ID of the responder and the transac-
tion ID. Combining these identifies a unique packet despite the possibility of otherwise conflicting transaction IDs.
3.4.7 sRIO Packet Blockage and Priorities
The SerB is not a switch and should not be involved in blocking packets. Despite this, the SerB may be unable to
transmit packets or packets may be blocked by downstream devices, requiring the SerB to hold and retransmit packets.
When connected to the PPS, the SerB should not be reordering packets based upon priority, because packets are issued
based upon time in the buffer and not priority.
When the SerB is used in non-PPS applications, it may be necessary to transmit packets based upon priority. Blocked
packets would be held and transmitted after subsequently received higher priority packets have been transmitted. In this
situation, blockage may develop if the inflow to the SerB exceeds or equals the outflow. Typically higher priority packets
would be initiated for command and symbol passing.
3.4.8 The sRIO Write Packet, Type 5, Special Considerations
The SerB may receive and issue both type 5, NWRITE and NWRITE_R packets. The SerB has no ability to issue or
receive any of the three ATOMIC packets. The wrsize accompanying the data will be stored as part of the packet header in
the SerB to allow correct identification of the packet length for subsequent transmission of the packet as the packet leaves
the SerB.
sRIO Type 5 packets assume the recipient device is addressable as a side address memory. The SerB is a FIFO and
will store the data seqentially and transmit data sequentially, regardless of the address accompanying the data. The
address will be stored as part of the packet header in the SerB, and may be used when the packet is again transmitted.
Despite not using the addresses for data storage, the addresses are used in some applications to detect missing
packets.
3.4.9 The sRIO Maintenance Packet, Type 8, Special Considerations
The sRIO Maintenance Packet is a Type 8 packet and is used for programming and/or reading the CARs and CSRs. In
addition, the Port-write maintenance packet may be generated as an error response as defined by the sRIO Error Manage-
ment Specification.
The sRIO Maintenance Packet allows in-band control of the SerB configuration. The RIO specifications define a
number of registers for end-point devices, which is described in the Register section.
sRIO maintenance packets are Type 8 packets and have the ftype field set to 1000b. These packets are described in
section 4.1.10 of the sRIO input/Output Logical spec. In addition, information on the tt and hop count can be found in
section 1.3 of the Common Transport Specification. An example of the structure of a type 8 packet is shown in Figure 7.
The configuration registers are all 32 bits or less, and all packets will carry 32 bits regardless of whether all 32 bits are
needed.
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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.