K21F USB issue

[AlvinLin1933]

When use K21F to replace K21D, USB can't communicate with Tablet and the other device, the buzzer and LED function can work, try 5pcs, the issue is the same. would you please advise how to fix it ?

[Pavel_Hernandez]

Hello, my name is Pavel, and I will be supporting your case, could you elaborate further about the communication through USB? Are you using the same bin, or do you have 2 different compile projects?

I say that because the MCU has a different frequency and needs to use the appropriate compilation, 120 MHz vs 50 MHz.

Best regards,
Pavel

[AlvinLin1933]

Hi Pavel :

    After completed the programming, Tablet can't recognize the USB K21F device.

[Pavel_Hernandez]

Hello, sorry for the late response I found on the SDK builder the K21F has an example on the SDK, could you try any example that your similar application, I want to know if the behavior is the same. 

The other thing could you elaborate further on the issue?

Best regards,
Pavel

[AlvinLin1933]

Hi Pavel :

    Please refer the enclosed png, when set the USBx_USBTCR0[USBRESET] bit manually, it seems fix the USB issue, would you have the other suggestion ?

[Pavel_Hernandez]

Hello, I found the following thread maybe could help you.

Delay needed before setting USB0_CTL? - NXP Community

Best regards,
Pavel