Successfully ran the "USB Generic Bulk Device (usb_dev_bulk)" sample program on the EK-TM4C123GXL lauchpad.
Then using my own board, with Code Composer Studio Version: 5.5.0.00077 on part TM4C123GH6PGE with a 16 MHz crystal, I am unable to successfully connect to a PC. Many things could go wrong on the hardware side, but the waveforms look okay. On the code side this example does not require much setup other than getting the pins set right. Using a tool called Device Monitoring Studio version 7.10 in the structure view I get this when I plug in:
USB_DP is blue, USB_DM is red, signals look better than the launchpad.
Has anyone experienced the device connecting to the system and then immediately disconnecting? If so any hints about where to investigate?
Would the fact that the monitor shows "U.S.B." in bytes 0x0a to 0x0f prove that the signal path is okay?