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Kinetis k20 USB Stack v4.1.1 troubles

Question asked by Cody Rigney on Oct 17, 2014
Latest reply on Jun 25, 2015 by Cody Rigney

I am having an issue that I thought was similar to some posts on this forum where I am receiving interrupts from the USB, but I never enter the TOK_DNE condition. I am using the USB_CDC_CLASS component of USB Stack v4.1.1.  I thought maybe doing the MPU_CESR = 0 would fix it, but my project doesn't have this variable (I am using CW 10.6 and processor expert, no OS).  So I searched the internet and found this:

 

#define MPU_BASE_ADDR 0x4000D000

#define MPU_CESR      (*(volatile uint32_t *) (MPU_BASE_ADDR + 0x00))

 

But I don't know if it's correct because when I set MPU_CESR = 0 the code stops running and in debug I'm stuck in PE_DEBUGHALT(). 

 

I also saw a post where putting the USB descriptors in RAM fixed the problem, but I don't know where the descriptor is or how to make sure it's in RAM.

 

I would appreciate anyone's help.  Thank you!

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