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Honored Contributor I
699 Views

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?
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Honored Contributor I
14 Views

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.
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Honored Contributor I
14 Views

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

Like I said before, read the documentation.
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Honored Contributor I
14 Views

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

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Highlighted
Honored Contributor I
14 Views

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."
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Highlighted
Honored Contributor I
14 Views

 

--- 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 ?
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