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Altera_Forum's avatar
Altera_Forum
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12 years ago

Is it possible to "gluelessly" connect several Altera IPs via Avalon-ST interface?

Hello!

Is it possible to "gluelessly" connect:

- Clocked Video Input/Output IP ( from VIP suite )

- Altera SGDMA IP

- Altera PCIe x 4 Hard IP

between each other via Avalon-ST interface in Cyclone IV GX?

I expect, that Avalon-ST interface will allow me to easily connect these IPs to make the following Qsys elements:

1). Clocked Video Input -> SGDMA IP-> PCIe Hard IP

2). PCIe Hard IP -> SGDMA IP-> Clocked Video Output

Is it really easy and can be done without any "glue" logic?

Maybe there is a reference design for these dataflows?

6 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    12 years ago

    No, it is not.

    SGDMA streaming input/output does not know anything about Avalon-ST Video (VIP suite) protocol.

    Read this:

    http://www.altera.com/literature/ug/ug_vip.pdf

    See page 34:

    "The MegaCore functions in the Video and Image Processing Suite use the Avalon-ST

    Video protocol. The Avalon-ST Video protocol is a packet-oriented way to send video

    and control data over Avalon-ST connections. Using the Avalon-ST Video protocol

    allows the construction of image processing data paths which automatically configure

    to changes in the format of the video being processed. This minimizes the external

    control logic required to configure a video system."

    The Avalon-ST video protocol is a subset of the Avalon-ST protocol.

    There are various kinds of packets that are defined by the VIP protocol

    that you must handle appropriately.

    The SGDMA block knows nothing about how to parse these.

    That is why you need an Avalon-ST to Avalon-ST Video converter block

    if you want to connect anything from the VIP suite to the SGDMA.
  • Altera_Forum's avatar
    Altera_Forum
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    12 years ago

    Hi, gwall!

    Take a look at the attached screenshot.

    It shows CVI connected to SGDMA without any errors.

    "Insert avalon-st adapter" QSys function was used to insert needed convertors.
  • Altera_Forum's avatar
    Altera_Forum
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    12 years ago

    Just because QSYS does not show an error, does not mean it will work.

    Like I said before, read the documentation.
  • Altera_Forum's avatar
    Altera_Forum
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    12 years ago

    It seems to me, that inserted Avalon-ST Adapters are in fact "Avalon-ST Video -> Avalon-ST" converter blocks.

  • Altera_Forum's avatar
    Altera_Forum
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    12 years ago

    --- Quote Start ---

    From:

    http://www.altera.com/literature/manual/mnl_avalon_spec.pdf

    Page 35:

    "All Avalon-ST source and sink interfaces are not necessarily interoperable. However,

    if two interfaces provide compatible functions for the same application space,

    adapters are available to allow them to interoperate."

    --- Quote End ---

    Does that quote means, that inserted Avalon-ST Adapters ( in the attached screenshot ) are in fact "Avalon-ST Video -> Avalon-ST" converter blocks ?