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Hi all,
I'm using ST's CubeMX implementation on a F4 discovery board. I use ST's USB middlewares with FreeRTOS.
When I get a special OutputReport from PC side I have to answer nearly immediately (in 10-15 ms). Currently I cannot achieve this timing and it seems my high priority tasks can interrupt the USB callback. What do you think, is it possible? Because it's generated code I'm not sure but can I increase the priority of the USB interrupt (if there is any)?
Thank you,
David
10 to 15 ms is very slow, so I'm sure its possible.
Where is the USB callback function called from? If it is an interrupt then it cannot be interrupted by high priority RTOS tasks. Any non interrupt code (whether you are using an RTOS or not) can only run if no interrupts are running.
Without knowing the control flow in your application its hard to know what to suggest. How is the OutputReport communicated to you? By an interrupt, a message from another task, or some other way?
The callback which receive the data from PC is called from the OTGFSIRQHandler (it's the part of the HALPCDIRQHandler function). I think the problem is SysTickHandler's priority is higher than OTGFSIRQHandler and it's cannot be modified, but the scheduler shouldn't interrupt the OTGFSIRQHandler with any task handled by the scheduler. Am I wrong that the scheduler can interrupt the OTGFS_IRQHandler?
It seems you’re asking for a story based on the title Fundamentos Del Razonamiento Estadistico Sanchez Viera PDF — likely a textbook on statistical reasoning by an author named Sánchez Viera. Since I can’t access or distribute copyrighted PDFs, I’ll instead craft a short narrative inspired by the search for that very document. The PDF of Reason
Elena was in Chicago. She couldn’t fly to Colombia. But Rosa added, “Don Jorge loves to talk. If you call him tomorrow at 4 PM our time, he might share the PDF if you prove you actually need to think , not just cite.”
She finished her thesis. The PDF never left her laptop. Years later, when a student emailed her asking for a copy, Elena didn’t just send the file. She asked her own question:
In a cramped, fluorescent-lit library carrel, graduate student Elena Martínez is desperate. Her thesis defense is in six weeks, and she’s missing the conceptual core of her research — a clear understanding of statistical reasoning. Her advisor keeps muttering, “Sánchez Viera. Chapter four.” But the book is out of print, and the only copy in the university system was checked out in 2019 and never returned.
A long silence. Then a chuckle.
That afternoon, she tried a different approach. Instead of searching for the PDF, she searched for people. On a university forum, a thread from 2016 mentioned a retired professor in Medellín, Colombia, who had studied under Sánchez Viera. One comment included an email address ending in “@udea.edu.co” — inactive, probably.
Two hours later, Elena opened Fundamentos Del Razonamiento Estadistico — a scanned, slightly crooked PDF, handwritten notes in the margins from 1998. Chapter four was indeed the heart: “El razonamiento no es cálculo; es coraje para dudar.” ( Reasoning is not calculation; it’s the courage to doubt. )
Thank you for the answer, I think I'm a bit confused with the Cortex ISR priorities :-)
What I can observe is if I use a much higher osDelay in my high priority task I can respond for the received USB message much faster. This is why I think tasks can mess up with my OTG interrupt.
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