This value provides control for S2MM transfers from stream to memory map.
Figure 1. S2MM_CONTROL
| Bits | Field Name | Description |
|---|---|---|
| 31 to 28 | Reserved | These bits are reserved and should be set to zero. |
| 27 | RXSOF | Start of Frame. Flag indicating the first buffer to be processed.
This flag is set by the sw/user to indicate to AXI DMA that this
descriptor describes the start of the packet. The buffer associated
with this descriptor is received first.
This is applicable only when AXI_DMA is configured in Micro mode. |
| 26 | Receive End Of Frame | End of Frame. Flag indicating the last buffer to be processed.
This flag is set by the sw/user to indicate to AXI DMA that this
descriptor describes the end of the packet. The buffer associated
with this descriptor is received last.
This is applicable only when AXI_DMA is configured in Micro mode. |
| 25 to 0 | Buffer Length | This value indicates the amount of space in bytes available for
receiving data in an S2MM stream. The usable width of buffer length
is specified by the parameter, Width of Buffer Length Register. A
maximum of 67,108,863 bytes of transfer can be described by this
field. Note: The total
buffer space in the S2MM descriptor chain (that is, the sum of
buffer length values for each descriptor in a chain) must be, at
a minimum, capable of holding the maximum receive packet size.
Undefined results occur if a packet larger than the defined
buffer space is received.
Note: Setting the Buffer Length Register Width smaller
than 26 reduces FPGA resource utilization.
Note: When configuring the
AXI_DMA in Micro mode, this value should not exceed the
following equation:
(S2MM Memory Mapped Datawidth/8)*Burst_length - 1 |