Texas Instruments TMS320C645X User Manual
Page 50
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SRIO Functional Description
Table 20. TX Buffer Descriptor Field Definitions (continued)
Field
Description
ownership
Ownership: Indicates ownership of the message and is valid only on sop. This bit is set
by the host and cleared by the port when the message has been transmitted. The host
uses this bit to reclaim buffers.
0: The message is owned by the host
1: The message is owned by the port
eoq
End Of Queue: Set by the port to indicate that all messages in the queue have been
transmitted and the TX queue is empty. End of queue is determined by the port when
the next_descriptor_pointer is zero on an eop buffer. This bit is valid only on eop.
0: The Tx queue has more messages to transfer.
1: The Descriptor buffer is the last buffer in the last message in the queue.
Teardown_Complete
Teardown Complete: Set by the port to indicate that the host commanded teardown
process is complete, and the channel buffers may be reclaimed by the host.
0: The port has not completed the teardown process.
1: The port has completed the commanded teardown process.
retry_count
Message Retry Count: Set by the CPU to indicate the total number of retries allowed
for this message, including all segments. Decremented by the port each time a
message is retried.
000000b: Infinite Retries
000001b: Retry Message 1 time
000002b: Retry Message 2 times
. . .
111111b: Retry Message 63 times
cc
Completion Code:
000: Good Completion. Message received a done response.
001: Transaction error. Message received an error response. *
010: Excessive Retries. Message received more than retry_count retry responses.
011: Transaction timeout. Transaction timer elapsed without any message response
being received.
100: DMA data transfer error
101: Descriptor Programming error
110: TX Queue Teardown Complete
111: Outbound Credit not available.
* An ERROR transfer completion code indicates an error in one or more segments of a
transmitted multi-segment message.
message_length
Message Length: Message Length – Written by the CPU to specify the number of
double-words to transmit. Message payloads are limited to a maximum size of 512
double-words (4096bytes).
000000000b: 512 double words
000000001b: 1 double word
000000010b: 2 double words
. . .
111111111b: 511 double words
Dest_id
Destination Node Id: Unique Node identifier for the Destination of the message.
pri
Message Priority: Specifies the SRIO priority at which the message will be sent.
Messages should not be sent at a priority level of 3 because the message response is
required to promote the priority to avoid system deadlock. It is the responsibility of the
software to assign the appropriate outgoing priority.
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Serial RapidIO (SRIO)
SPRU976 – March 2006