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USB attach event at code start up

Question asked by Richard Lysaght on Mar 19, 2016
Latest reply on Mar 21, 2016 by Bob Paddock

Dear NXP community,

 

I have a customer struggling a little with the Kinetis USB stack.  Looks like everything is working except at power up the USB stick isn't always recognized if it is already attached.  Here is the note from the customer:

 

We are using the baremetal USB stack in our SubDrive design
(this is in KDS but does not use KSDK).  We recently moved it to newer
micros and the USB was working fairly well until we put optimization on in the
code.  We started to get watchdog resets due to the USB stack.  We
investigated this some and moved the USB_host_init() into the startup
components_init() section of the code.  The reset issue is resolved, but
now it sometimes does not recognize an attached USB thumb drive during power
up.

 

We don’t believe the attach event is occurring but don’t
understand in the USB stack what generates the attached event.  Is there
any documentation on what generates this event?

 

Anyone have any helpful suggestions?

 

Thanks in advance.

 

Rich

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