Bits
Name
Description
[153:146]
DMA Descriptor ID
Specifies up to 128 descriptors.
[158:154]
Reserved
—
[159]
Immediate Write
When set to 1'b1, the Write DMA Engine performs an
Immediate Write
. The
Immediate Write
provides a fast
mechanism to send a Write TLP upstream. The descriptor stores
the 32-bit payload, replacing the
Source Low Address
field of
the descriptor.
DMA Descriptor Status Bus when Instantiated Separately
Read DMA and Write DMA modules report status to the Descriptor Controller on the
RdDmaTx-
Data_o[31:0]
or
WrDmaTxData_o[31:0]
bus when one of the following trigger events occurs:
• A descriptor is activated
• A descriptor completes successfully
The following table shows the mappings of the triggering events to the DMA descriptor status bus:
Table 6-11: DMA Status Bus
Bits
Name
Description
[31:9]
Reserved.
—
[8]
Done
When asserted, a single DMA descriptor has completed success‐
fully.
[7:0]
Descriptor ID
The ID of the descriptor whose status is being reported.
Descriptor Controller Interfaces when Instantiated Internally
Read Descriptor Controller Avalon-MM Master Port
The Read Descriptor Controller Avalon-MM master port drives the TX Avalon-MM slave port. This port
drives single dword transactions to the Arria 10 Avalon-MM DMA for PCIe. The Read Descriptor
Controller uses this port to write descriptor status to the PCIe domain and possibly to MSI when MSI
messages are enabled.
Table 6-12: Read Descriptor Controller Avalon-MM Master Interface
Signal Name
Direction
Description
RdDCMAddress_o[63:0]
Output
Specifies the address for the read data.
RdDCMByteEnable_
o[3:0]
Output
Specifies which data bytes are valid.
RdDCMReadDataValid_i
Input
When asserted, indicates that the read data is valid.
UG-01145_avmm_dma
2015.11.02
DMA Descriptor Status Bus when Instantiated Separately
6-11
IP Core Interfaces
Altera Corporation
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