www.ti.com

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

Issued￿By

Master

Request

Packet￿Issued

Acknowledge

Symbol

Operation

Completed￿for

Master

Fabric

Acknowledge

Symbol

Request￿Packet

Forwarded

Response

Packet

Forwarded

Acknowledge

Symbol

Target

Acknowledge

Symbol

Response￿Packet

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 16-bit pad of value 0000h is added to the end of the packet, after the CRC (not shown). Bit fields that are defined as reserved are assigned to logic 0s when generated and ignored when received. All request and response packet formats are described in the RapidIO Input/Output Logical Specification and MIessage Passing Logical Specification.

SPRUE13A –September 2006

Serial RapidIO (SRIO)

23

Submit Documentation Feedback

Page 23
Image 23
Texas Instruments TMS320TCI648x manual Operation Sequence, Example Packet Streaming Write