Altera cyclone V Technical Reference page 1253

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Receive Descriptor Field 0 (RDES0)
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Altera Corporation
Bit
DE: Descriptor Error
When set, this bit indicates a frame truncation caused by a frame
that does not fit within the current descriptor buffers, and that the
DMA does not own the Next descriptor. The frame is truncated. This
bit is valid only when the Last Descriptor (RDES0[8]) bit is set.
SAF: Source Address Filter Fail
When set, this bit indicates that the SA field of frame failed the SA
Filter in the MAC.
LE: Length Error
When set, this bit indicates that the actual length of the frame
received and that the Length/ Type field does not match. This bit is
valid only when the Frame Type (RDES0[5]) bit is clear.
OE: Overflow Error
When set, this bit indicates that the received frame was damaged
because of buffer overflow in MTL.
Note: This bit is set only when the DMA transfers a partial frame to
the application, which happens only when the RX FIFO buffer is
operating in the threshold mode. In the store-and-forward mode, all
partial frames are dropped completely in the RX FIFO buffer.
VLAN: VLAN Tag
When set, this bit indicates that the frame to which this descriptor is
pointing is a VLAN frame tagged by the MAC. The VLAN tagging
depends on checking the VLAN fields of the received frame based
on the Register 7 (VLAN Tag Register) setting.
FS: First Descriptor
When set, this bit indicates that this descriptor contains the first
buffer of the frame. If the size of the first buffer is 0, the second
buffer contains the beginning of the frame. If the size of the second
buffer is also 0, the next descriptor contains the beginning of the
frame.
LD: Last Descriptor
When set, this bit indicates that the buffers pointed to by this
descriptor are the last buffers of the frame.
Description
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2016.10.28
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Ethernet Media Access Controller
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