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Is file I/O as USB host MQX friendly?

Question asked by David Pfaltzgraff on Jul 21, 2015
Latest reply on Jul 23, 2015 by Kan_Li

I took the example found in C:\Freescale\KSDK_1.2.0\examples\frdmk22f\demo_apps\usb\host\msd\msd_fatfs\mqx\kds and have expanded it to include other tasks under MQX. The idea is to have small background tasks that use interrupts to collect data and then log these to a USB drive. However, it seems to me that when the USB drive is active it blocks all the other tasks from running.

 

The first clue was that even before plugging in a USB drive, I needed to add an OS_Time_delay() statement at the top of the primary loop of fat_demo() before the other tasks were able to run. That was OK. But, when I plug in a USB drive, it appears that the other tasks don't get a time slice.

 

Am I reading this right?

 

If so, what can I do to get the USB file I/O to be MQX friendly and share the idle time?

 

Thanks

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