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lwIP_Demo_Rowley_ARM7 and CDC receiving byte

Posted by Steve MULLER on August 13, 2008

I am new to FreeRTOS. Seems to be a great OS.
I try to modify the demo code to have a simple ping-pong over the CDC.

I add the following lines to several files :

* lwIP_Demo_Rowley_ARM7\USB\USB-CDC.c:262
unsigned vUSBReceiveByte( portCHAR * cByte )
if ( uxQueueMessagesWaiting( xRxCDC ) != 0 )
xQueueReceive( xRxCDC, cByte, usbNO_BLOCK );
return 1;
return 0;

* lwIP_Demo_Rowley_ARM7\USB\USB-CDC.h:99
unsigned vUSBReceiveByte( portCHAR * cByte );

* lwIP_Demo_Rowley_ARM7\main.c:313
if ( vUSBReceiveByte( &cTxByte ))
vUSBSendByte( cTxByte );

With this code the OS seems to be completly frozen.

What is false in my code ? And why ?

Thanks in advance.


P.S. : I use the V5.0.2 of FreeRTOS.

RE: lwIP_Demo_Rowley_ARM7 and CDC receiving byte

Posted by Dave on August 13, 2008
I think this demo uses an idle task hook function or something similar to continuously send characters in the background. Did you remove this code first? Just setting configUSE_IDLE_HOOK to 0 in FreeRTOSConfig.h might be enough.

RE: lwIP_Demo_Rowley_ARM7 and CDC receiving byte

Posted by Steve MULLER on August 13, 2008

Currently, I use this hook to handle the Queue over vUSBReceiveByte().
I removed the code who continuously send characters.



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