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Registered: ‎10-15-2010

LWIP problem, cannot send small frame



I'm using a PPC440 with a Virtex5.

In order to communicate over the LAN, i implemented the LWIP1.3.0 stack. It's working quite well but i still have some strange errors that i'm not able to handle.

My problem is when i'm sending small frame, for example 20bytes, i got an ERROR -4 from the function tcp_write().


This error does not happen each time i send a small frame but very often. Instead of that, if i send a big frame, let's say 1200bytes, i never have this error, everything goes well.


Can someone help me on this problem please. I'm really confused and i cannot continue my application cause of that.

Thank you so much for your futur advises.


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Registered: ‎10-15-2010

please help !!!

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Xilinx Employee
Xilinx Employee
Registered: ‎08-01-2007

Try to run xapp1026 echo server example or the echo server example in SDK new project templates.

Echo server sends only one byte every time if you telnet to the board and type anything in the console.

Make sure the echo server software work fine on your hardware platform and check what's the setup difference.
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Registered: ‎10-15-2010

I tryed to use the xapp1026 as you advised me. I was able to send small frame by the echo program.

Problem is the code that i'm trying to debug and the echo program are quite different, so it's difficult to compare.


Anyway, even if i try to reduce my custom code to the minimu just for one "send" ad we can see on the echo program it's still does not work.


Do you have so idea or track that i can follow ??




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