6 years, 7 months ago.

USBSerial causes regular UART on LPC1768 to hang


I wonder if anyone else has experienced this problem before. I am using the LPC1768 microcontroller on the mbed application board. So I got two USB ports. The one on the app board is enabled using USBSerial (virtual serial), and the one on the LCP1768 board is regular Serial going through the mbed interface controller.

I have a program that uses both serial interfaces. After I run the program for a few minutes, the regular serial interface will sometimes stop responding, However, my code is still running fine (LEDs are blinking as expected), and the USBSerial interface is still working too. When I looked at my Device Manager, I see both COM ports are still listed. What makes this problem serious is that I need to unplug both USB cables to resolve it. Pressing the LPC1768 reset button does not fix the hanging issue.

Can this be a problem related to the mbedSerial.sys driver on Windows 7? I only have one laptop, so I can't check on other PCs.

Thank you!

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