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[FreeRTOS Home] [Live FreeRTOS Forum] [FAQ] [Archive Top] [November 2011 Threads] Stack Overflow / Underflow with serial comPosted by Sigma on November 19, 2011 Hi, I use FreeRTOS 7.0.2 on the PIC18F4685. I create a simple task that get data from the serial port. If I send data slowly on the port of the PIC, it work well, but if I send a big amount of data, I have stackoverflow/underflow. If I put usStackDepth of 200, the problem disapear, but why ? This is the code of my task : “static portTASK_FUNCTION( vComRxTask, pvParameters ) { signed char cByteRxed;
/* Just to stop compiler warnings. */ ( void ) pvParameters;
for( ;; ) { /* Block on the queue that contains received bytes until a byte is available. */ if( xSerialGetChar( xPort, &cByteRxed, comRX_BLOCK_TIME ) ) { if( cByteRxed == '1' ) { vParTestSetLED( 2, pdTRUE ); } else { vParTestSetLED( 2, pdFALSE ); } } } }” Thanks
RE: Stack Overflow / Underflow with serial comPosted by Richard on November 21, 2011 “If I put usStackDepth of 200, the problem disapear, but why ?” Well you haven't said what you changed it from, but I would guess because when you have it lower than that you are overflowing the stack? Regards.
RE: Stack Overflow / Underflow with serial comPosted by Sigma on November 24, 2011 Sorry I change it at the creation of the task : “xTaskCreate( vComRxTask, ( signed char * ) "COMRx", 200, NULL, uxPriority, ( xTaskHandle * ) NULL );” “Well you haven't said what you changed it from, but I would guess because when you have it lower than that you are overflowing the stack?” Yes but why is there an overflow. There is a buffer for the input data of the serial link. If too much data is incoming, I would understand that the OS don't take all the data, but why an overflow appear ? With 200, it work, but what is the genrel way to estimate the value of this stack ? Thanks.
RE: Stack Overflow / Underflow with serial comPosted by Sigma on December 23, 2011 Please ?
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