AnsweredAssumed Answered

USB min frequency

Question asked by Martin Dusek on Sep 16, 2014
Latest reply on Sep 16, 2014 by Mark Butcher

Hello,

what's the min CPU frequency Freesscale bare metal USB stack (namely generic HID device) can reliably run on KL26?

I clock USB module 48 MHz.

 

When I compile my C code without optimization and CPU runs on 12 MHz I mainly get "USB device not recognized" error in Windows when I connect my device to PC (90% probability I will get the error)

 

No optimization and 24 Mhz CPU leads to "USB device cannot start, Code 10" in Windows (10 % probabality I will get the error)

 

Optimization and 12 MHz CPU leads to "USB device cannot start, Code 10" in Windows (10 % probabality I will get the error)

 

Optimization and 24 Mhz leads to no error.

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