Table 7-15: DMA Descriptor Controller Registers for Read DMAs
The following tables describe the registers in the internal DMA Descriptor Controller. When the DMA Descriptor
Controller is externally instantiated, these registers are accessed through a BAR. The offsets must be added to the
base address for the read and write controllers. When the Descriptor Controller is internally instantiated these
registers are accessed through BAR0. The read controller is at offset 0x0000. The write controller is at offset
0x0100 when instantiated internally.
Address
Offset
Register
Access
Description
0x0000
RC Read Status and Descriptor
Base (Low)
R/W
Specifies the lower 32-bits of the base
address of the read status and descriptor
table in the Root Complex memory. This
address must be on a 32-byte boundary.
Internal software must program this
register after programming the upper 32
bits at offset 0x4. To change the
RC Read
Status and Descriptor Base (Low)
base address, all descriptors specified by
the
RD_TABLE_SIZE
must be exhausted.
0x0004
RC Read Status and Descriptor
Base (High)
R/W
Specifies the upper 32-bits of the base
address of the read status and descriptor
table in the Root Complex memory.
Software must program this register
before programming the lower 32 bits of
this register.
0x0008
EP Read Descriptor FIFO Base
(Low)
RW
Specifies the lower 32 bits of the base
address of the read descriptor FIFO in
Endpoint memory. The Read DMA
fetches the descriptors from Root
Complex memory. The address must be
the Avalon-MM address of the Descriptor
Controller's Read Descriptor Table
Avalon-MM Slave Port as seen by the
Read DMA Avalon-MM Master Port. You
must program this register after program‐
ming the upper 32 bits at offset 0x8.
7-18
DMA Descriptor Controller Registers
UG-01145_avmm_dma
2015.11.02
Altera Corporation
Registers
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