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SRIO Functional Description
SRIO endpoints are typically not connected directly to each other but instead have intervening connection fabric devices. Control symbols are used to manage the flow of transactions in the SRIO physical interconnect. Control symbols are used for packet acknowledgment, flow control information, and maintenance functions. Figure 5 shows how a packet progresses through the system.
Figure 5. Operation Sequence
Initiator
Operation
IssuedBy
Master
Request
PacketIssued
Acknowledge
Symbol
Operation
Completedfor
Master
Fabric
Acknowledge
Symbol
RequestPacket
Forwarded
Response
Packet
Forwarded
Acknowledge
Symbol
Target
Acknowledge
Symbol
ResponsePacket
Issued
Target
Completes
Operation
2.1.2.2Example Packet – Streaming Write
An example packet is shown as two data streams in Figure 6. The first is for payload sizes of 80 bytes or less, while the second applies to payload sizes of 80 to 256 bytes. SRIO packets must have a length that is an even integer of 32 bits. If the combination of physical, logical and transport layers has a length that is an integer of 16 bits, a
SPRUE13A | Serial RapidIO (SRIO) | 23 |