Hello I use project CDC Virtual COM Port, which I few change. My project has 2 endpoints. Bulk - out and Interrupt - in. I use standart function: CDC_Receive_HS (uint8_t* Buf, uint32_t *Len) - for receive data and CDC_Transmit_HS(uint8_t* Buf, uint16_t Len) - for transmit data. When I periodically call CDC_Transmit_HS in main program, I sometimes can't receive data from Bulk. Why ?
When I call CDC_Transmit_HS in USB SOF interrupt, I always receive data from Bulk and It work good.