8 years, 10 months ago.

How to repair MBED drivers for Windows?

I am using a FRDM K64. I am working on a Windows 8.1 PC. My MBED development has worked well for several months but now there appears to be a problem with the drivers in my laptop. The first symptom was that my MBED drive disappeared from the windows explorer. Thinking this was a hard crash of the board I went back to the bootloader and reinstalled the MBED software, the Bootloader drive was recognized so I could reload the software. Upon power cycle, the MBED drive did not appear. I then moved the board to a second USB port on my PC and the MBED drive reappeared. I went back to the original port USB port and MBED returned. Thinking I had solved the problem I began work again. The problem came back but this time I could not restore the connection to my first USB and then the second USB port was experiencing the same behavior. I had one last USB port. And MBED would appear when plugged into that port.

Thinking this is a driver problem I went to the hardware manager and uninstalled the driver for the mbed composite device in the hardware manager and selected the delete driver from the system option.

I then plugged the device back in to the first USB port and the driver reinstalled and the MBED device showed up on the explorer and I was able to download a program to it. I downloaded a simple Hello World program, a loop with a 1 sec wait and then repeated printing out the same message.

I then had to reload the serial port driver for windows. Once that was installed the MBED drive again disappeared from the explorer window and would not return on power cycle. I started Tera term and the message would print about 4 or 5 times to the window and then stop, restarting teraterm again and about 4 or 5 more messages would print and then stop.

I have repeated this multiple times so that I could report my findings and it is consistent.

So to recap: Symptom: MBED drive no longer shows up on Windows explorer unless delete the MBED composite device driver and reload it. When I then reload the serial port drive the MBED drive no longer shows up. The serial port only works for a brief period of time before it stops responding. USB ports that have not been previously used on the project seem to work fine.

Any help you can provide to resolve these issues would be helpful.