"Hi everyone! I'm having an issue..." <- > <@stephen:crabsin.space> Hi everyone! I'm having an issue with USB CDC. Basically I want to constantly sends data from my stm32 to the host. > > I'm using rtic on an stm32f411. I have an interrupt handler set up to capture any OTG_FS interrupts and poll the usb device. In my idle task I send the string "hello world" over and over. It works about a dozen times and then stops. It looks like the otg_fs interrupt handler gets stuck in an infinite loop, as if the interrupt is never cleared Have you checked _all_ of the USB interrupt flags? I had a similar problem with ethernet and found a default-enabled ISR