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USB CDC dont work in debug

Question asked by o gaste on Apr 11, 2017
Latest reply on Apr 20, 2017 by o gaste

Hi all
I'm working on a STM32F303CC very simple board(just µC IMU and USB).
I need to use a USB Virtual COM (CDC) for a MtoM data transfer with a Windows PC
I set up BSP with STMCubeMx and compiling/debuging with Keil V5 with an STlink V2 in SWD mode
board and microcontrolers are powered by USB
all look's working great when I make a hard reset (just fresh power up) but if I try to make a soft reset like when entering in debug despite Virtual Com Port is well enumerated on windows side it could not open com port and no Usb transmit can be done on target side becase of Usb Device descriptor not defined in Usb Midle ware
does anyone faced the same issue or somthing similare ? I tried to use USBLyser to see what's wrong but I must admit I've not seen something particular when doing soft reset
thank's for any help