Altera Arria 10 Avalon-ST User Manual

Page 210

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Addr

Register Name

Bits[31:]24

Bit[23:16]

Bit[15:0]

0x1C

DMA Rd Cntl DW3

Reserved

Reserved

RCLAST–Idx of the last

descriptor to process

The following table describes the control fields of the of the DMA read and DMA write control registers.

Table 17-3: Bit Definitions for the Control Field in the DMA Write Control Register and DMA Read Control

Register

Bit

Field

Description

16

Reserved

17

MSI_ENA

Enables interrupts of all descriptors. When 1, the Endpoint

DMA module issues an interrupt using MSI to the RC when

each descriptor is completed. Your software application or BFM

driver can use this interrupt to monitor the DMA transfer status.

18

EPLAST_ENA

Enables the Endpoint DMA module to write the number of each

descriptor back to the EPLAST field in the descriptor table.

[24:20]

MSI Number

When your RC reads the MSI capabilities of the Endpoint, these

register bits map to the back-end MSI signals

app_msi_num

[4:0]. If there is more than one MSI, the default mapping if all

the MSIs are available, is:
• MSI 0 = Read

• MSI 1 = Write

[30:28]

MSI Traffic Class

When the RC application software reads the MSI capabilities of

the Endpoint, this value is assigned by default to MSI traffic class

0. These register bits map to the back-end signal

app_msi_

tc

[2:0].

31

DT RC Last Sync

When 0, the DMA engine stops transfers when the last

descriptor has been executed. When 1, the DMA engine loops

infinitely restarting with the first descriptor when the last

descriptor is completed. To stop the infinite loop, set this bit to

0.

The following table defines the DMA status registers. These registers are read only. In this table, Addr

specifies the Endpoint byte address offset from BAR2 or BAR3.

17-10

Chaining DMA Control and Status Registers

UG-01145_avst

2015.05.04

Altera Corporation

Testbench and Design Example

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