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5 years, 3 months ago.
EFM32 USBDevice CDC - does not enumerate on bus power
I'm trying out USBDevice library on EFM32 Leopard Gecko platform. It works fine, the CDC driver communicates nicely with the PC.
However, the device is not recognized (Windows 7) when plugged in only with device USB cable. The only way to get it running is to plug the debug interface first (giving power), then to plug the device USB cable.
Same thing with programming - after programming I need to physically unplug the USB device cable (with the programming cable plugged in), then plug the cable.
Any clue what might be wrong? Some timing problem?