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Altera_Forum's avatar
Altera_Forum
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16 years ago

Avalon Streaming Sink / Source Interface Signals

Hi Everybody!

I want to create a new SOPC component (say, N1) connect to Clocked Video Output (a component in Video Image Processing Suite). I generated a dout port, which is Avalon Streaming Source Interface. The dout port contains five signals to match the Clocked Video Output component. The five signals are: data, ready, valid, startofpacket and endofpacket. But an error message showed in Component Editor: "Error: N1_dout: The connection point has only some of the required packet signals".

Then I added an "empty" signal to my N1 component, the error message was gone. However, another error appeared in SOPC builder: "Error: N1_inst.dout/vga_out_inst.din: The source has a empty signal of 1 bits, but the sink does not". I know there is no empty signal in Clocked Video Output but when I deleted "empty" in my N1 component, above error (The connection point has only some of the required packet signals) comes again.

Can anybody help me to solve this problem?

5 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    The empty signal is used to tell a sink port how many symbols sent from the source port are invalid.

    So if you data width is 32 bits wide and your symbols are bytes (8 bits each) you would use an empty width of 2 bits. So it could be that your custom component with the source port isn't declaring the empty signal to be wide enough. Typically with video you treat RGB, YCbCr, etc... components as symbols so I suspect you'll probably need to do the same.

    The VIP documentation should tell you what the streaming format is for that component and you would just make sure that your custom component feeding the data matches it.
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    What version of the tools are you using. This was a known issue but was supposed to be fixed in 9.0. Basically the VIP suite does not use the "empty" signal. However, SoPC builder expected it to be there for Avalon Streaming Interfaces. The VIP components get by without the error but your own custom components don't.

    I'm pretty sure this is fixed in newer versions of the tool. However, if you want to keep using the older tools, you can get around the error by holding "Shift" or "Ctrl" (I can't remember which one) when you click the "Generate" button in SoPC builder. It will still flag the error but will go ahead and build the system anyway and everthing will work fine.

    Jake
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    To BadOmen: I tried different bits on empty and it is still not working. By the way, looks you are a Canadien fan, GO HABS GO!

    To jakobjones: I'm using Quartus II 8.0. I will try your method in SOPC Builder to generate the system and if it is not good, try to use 9.1 instead.

    Thank you both of you guys!