The DataMover S2MM function can be parameterized to enable support for stream
data transfer of an indeterminate number of bytes. This is defined as where the S2MM
is commanded (by the BTT command field) to transfer a fixed number of bytes, but it
is unknown how many bytes are actually going to be received from the incoming stream
interface (at the assertion of s_axis_s2mm_tlast).
Supporting this operation mode requires additional hardware in the S2MM function,
and additional fields in the status word indicating the actual count of the bytes
received from the stream interface for the commanded transfer, and whether the
tlast was received during the transfer.
The format of the S2MM status word with Indeterminate BTT Mode enabled is shown in the following figure and detailed in the following table. This status format does not apply to the MM2S DataMover status interface. See Indeterminate BTT Mode for more information.
| Bits | Field Name | Description |
|---|---|---|
| 31 | EOP | End of Packet: This bit indicates that the S2MM Stream input received a tlast assertion during the execution of the DataMover command associated with the status word. This is not an error condition. |
| 30 to 8 | BRCVD | Bytes Received: This field indicates the actual number of bytes received on the stream interface at the point where s_axis_s2mm_tlast was asserted by the Stream Master. |
| 7 | OKAY |
Transfer OKAY: This
bit indicates that the associated transfer command has been
completed with the OKAY response on all intermediate transfers. 0 = Command had a non-OKAY response during all associated transfers. 1 = Command had a OKAY response during all associated transfers. |
| 6 | SLVERR |
Slave Error:
Indicates the DataMover encountered a slave reported error condition
for the associated command. This is received by the response inputs
from the AXI4 interface. 0 = No Error 1 = Slave Asserted Error Condition |
| 5 | DECERR |
Decode Error:
Indicates the DataMover encountered an address decode error
condition for the associated command. This is received by the
response inputs from the AXI4
interface and indicates an address decode timeout occurred on an
address generated by the DataMover element while executing the
corresponding command. 0 = No Error 1 = Address Decode Error Condition |
| 4 | INTERR |
Internal Error:
Indicates the DataMover encountered an internal error condition for
the associated command. A BTT (Bytes to Transfer) value of 0 (zero)
in the command word can cause this assertion. Additional conditions are to be determined. 0 = No Error 1 = Internal Error Condition |
| 3 to 0 | TAG | TAG: This 4-bit field echoes the value of the TAG field of the associated input command whose completion generated the status. |