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STM32 USB Library NAKs OUT packets from host

Question asked by Brown.Elijah on Feb 1, 2017
Latest reply on Feb 23, 2017 by Lambert.Julie

I have the STMicro USB library configured as a full speed CDC device.  This is running on a STM32F405OG chip.  Everything works as expected but (very) occasionally it gets into a state where the device NAKs every OUT packet sent by the host, and this continues forever (see attached screenshot of the USB trace).  I haven't been able to figure out exactly what triggers this but it seems to happen when there is a lot of USB traffic going through the device.  Has anyone seen this before or have any ideas what is happening?