Altera cyclone V Technical Reference page 1232

cv_5v4
2016.10.28
A data buffer resides in the Host physical memory space, and consists of an entire frame or part of a frame,
but cannot exceed a single frame. Buffers contain only data, buffer status is maintained in the descriptor.
Data chaining refers to frames that span multiple data buffers. However, a single descriptor cannot span
multiple frames. The DMA skips to the next frame buffer when end-of-frame is detected. Data chaining
can be enabled or disabled.
Figure 17-4: Descriptor Ring Structure
Figure 17-5: Descriptor Chain Structure
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Descriptor 0 Descriptor 0
Descriptor 1
Descriptor 2
Descriptor n
Descriptor 0
Descriptor 1
Descriptor 2
Next Descriptor
Descriptor Lists and Data Buffers
Buffer 1 Buffer 1
Buffer 2 Buffer 1
Buffer 1
Buffer 2
Buffer 1
Buffer 2
Buffer 1
Buffer 2
Buffer 1
Buffer 1
Buffer 1
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