Arria V GZ Avalon-MM Interface for PCIe Solutions: User Guide

ID 723696
Date 5/21/2017
Public
Document Table of Contents

4.2. RX Avalon-MM Master Signals

The RX Avalon-MM Master module translates read and write TLPs received from the PCIe link to Avalon-MM requests for Qsys components connected to the interconnect. Up to six Avalon-MM Master interfaces can be enabled. Each master interface drives one of the six Base Address Registers (BARs). This module allows other PCIe components, including host software, to access other Avalon-MM slaves connected in the Qsys system.

The following restrictions apply to the BARs:

  • When you instantiate the internal descriptor controller with 32-bit addresses, BAR0 drives its Avalon-MM slave interface and is not available for other purposes. For 64-bit address, BAR0 and BAR1 are not available.
  • BAR2 or BAR2 and BAR3, for 64-bit addresses support single dword access and bursting.
  • BAR3 (when used as a 32-bit master), BAR4, and BAR5 support single dword access only.
Table 20.  Avalon-MM RX Master Interface Signals Signals that include Bar number 0 also exist for BAR1–BAR5 when additional BARs are enabled.

Signal Name

Direction

Description

RxmWrite_<n>_o

Output

Asserted by the core to request a write to an Avalon-MM slave.

RxmAddress_<n>_o[<w>-1:0]

Output

The address of the Avalon-MM slave being accessed.

RxmWriteData__<n>_o[<w>-1:0]

Output

RX data being written to slave. <w> = 64 or 128 for the full-featured IP core. <w> = 32 for the completer-only IP core.

RxmByteEnable_<n>_o[<w>-1:0]

Output

Byte enables for write data.

RXMBurstCount_<n>_o[6 or 5:0]

Output

>The burst count, measured in qwords, of the RX write or read request. The width indicates the maximum data that can be requested. The maximum data in a burst is 512 bytes. This optional signal is available for BAR2 only when you turn on Enable burst capabilities for RXM BAR2 ports.

RXMWaitRequest_<n>_i

Input

Asserted by the external Avalon-MM slave to hold data transfer.

RXMRead_<n>_o

Output

Asserted by the core to request a read.

RXMReadData_<n>_o[<w>-1:0]

Input

Read data returned from Avalon-MM slave in response to a read request. This data is sent to the IP core through the TX interface. <w> = 64 or 128 for the full-featured IP core. <w> = 32 for the completer-only IP core.

RXMReadDataValid_<n>_i

Input

Asserted by the system interconnect fabric to indicate that the read data is valid.

RxmIrq_i[<m>:0], <m>< 16

Input

Indicates an interrupt request asserted from the system interconnect fabric. This signal is only available when the CRA port is enabled. Qsys-generated variations have as many as 16 individual interrupt signals (<m>≤15). If rxm_irq_<n>[<m>:0] is asserted on consecutive cycles without the deassertion of all interrupt inputs, no MSI message is sent for subsequent interrupts. To avoid losing interrupts, software must ensure that all interrupt sources are cleared for each MSI message received.

The following figure illustrates the RX master port propagating requests to the Application Layer and also shows simultaneous, DMA read and write activity

Figure 7. Simultaneous DMA Read, DMA Write, and Target Access