Altera cyclone V Technical Reference page 959

cv_5v4
2016.10.28
Internal DMA Controller Descriptors
The internal DMA controller uses these types of descriptor structures:
• Dual-buffer structure—The distance between two descriptors is determined by the skip length value
written to the descriptor skip length field (
Figure 14-4: Dual‑Buffer Descriptor Structure
• Chain structure—Each descriptor points to a unique buffer, and to the next descriptor in a linked list.
Figure 14-5: Chain Descriptor Structure
Internal DMA Controller Descriptor Address
The descriptor address must be aligned to the 32-bit bus. Each descriptor contains 16 bytes of control and
status information.
SD/MMC Controller
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The Distance Between 2
Descriptors Is Determined
by the DSL Value Programmed
in the BMOD Register
†
Descriptor A
Descriptor B
Descriptor C
†
Internal DMA Controller Descriptors
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) of the bus mode register (
dsl
Descriptor A
Descriptor B
Descriptor C
Data Buffer
Data Buffer
Data Buffer
†
).
bmod
Data Buffer 1
Data Buffer 2
Data Buffer 1
Data Buffer 2
Data Buffer 1
Data Buffer 2
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14-13
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