Our design uses the USB interface on the MSP430. The design is battery powered. The design allows the user to connect to the USB input in order to configure, read data or download archives.
Everything works fine if the USB is connected soon after power-up. If the board is left with battery power and no USB for 1-3 days and USB is then plugged in, the PC recognizes the port but the board does not respond to polling. Only by power-cycling the board does it work again. IF USB is connected and communicating continuously it never fails. Only with long term absence of USB does it fail.
USB is the only thing that stops working. All other aspects of the MSP continue to function properly including several other communication ports.
We have looked over the Errata for the part and made all suggested settings for USB but the problem still happens. We have confirmed that there are no stack overflow problems and have locked the 2k of RAM dedicated to theUSB. The problem occurs on many and all boards tested.
Where should we be looking to track down this problem?
Thank you
