Texas Instruments TMS320TCI648x - Manual (Page 52)

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3 reserved retry_count cc message_length
13 21 5 25 9 17 1 30 14 22 6 26 10 18 2 28 12 20 4 24 8 16 0
Bit Fields
next_descriptor_pointer
buffer_pointer
dest_id pri tt ssize mailbox port_id
Word
Offset
SRIO Functional Description
Table 20. TX DMA State Completion Pointer (CP) (Address Offset 58h–5BCh)
Bit Name Description
31–0 TX Queue TX Queue Completion Pointer: This field is the DSP core memory address for the transmit queue
Completion Pointer completion pointer. This register is written by the DSP core with the buffer descriptor address for
the last buffer processed by the DSP core during interrupt processing. The port uses the value
written to determine if the interrupt should be deasserted.
Figure 22. TX Buffer Descriptor Fields
Table 21. TX Buffer Descriptor Field Definitions
Field Description
next_descriptor_pointer Next Descriptor Pointer: The 32-bit word aligned memory address of the next buffer
descriptor in the TX queue. This is the mechanism used to reference the next buffer
descriptor from the current buffer descriptor. If the value of this pointer is zero then the
current buffer is the last buffer in the queue. The DSP core sets the
next_descriptor_pointer.
buffer_pointer Buffer Pointer: The byte aligned memory address of the buffer associated with the
buffer descriptor. The DSP core sets the buffer_pointer.
sop = 1 Start of Message: Indicates that the descriptor buffer is the first buffer in the message.
•
This bit will always be set as this device only supports one buffer per message.
eop = 1 End of Message: Indicates that the descriptor buffer is the last buffer in the message.
• This bit will always be set as this device only supports one buffer per message.
ownership Ownership: Indicates ownership of the message and is valid only on sop. This bit is set
by the DSP core and cleared by the port when the message has been transmitted. The
DSP core uses this bit to reclaim buffers.
0: The message is owned by the DSP core
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 DSP core commanded
teardown process is complete, and the channel buffers may be reclaimed by the DSP
core.
0: The port has not completed the teardown process.
1: The port has completed the commanded teardown process.
52 Serial RapidIO (SRIO) SPRUE13A – September 2006
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