USB OTG_FS (device mode) CDC-ACM: IN endpoint freezes
We are working on radio dongle application using STM32F411/13. We have mostly everything working, except for a lingering issue with USB. Details of the issue are as below:
- The radio dongle application enumerates as a CDC-ACM device as expected.
- And we can send/receive data over USB to the dongle using a host application.
- The host application sends the data to be transmitted to the radio dongle over USB.
- And the dongle application sends back received data to host app.
- And this is will be continuously repeated.
- But, after a while we see that USB OTG device device stops responding and on debugging further it was found that, it is stuck waiting for an IN transfer complete interrupt which seems to never fire.
We also tried different ways of reproducing this issue, and the easiest way to do so was by closing the host application while the communication between USB host and device is ongoing. So, if i abruptly close the host application and if the OTGFS device happens to have started the IN transfer it ends up in this scenario where IN transfer complete interrupt never fires.
Next, if i try to reopen the host application it does not work and OTG FS device is stuck in this state until we do a power cycle. I do not observe this issue with a different hardware platform that we have (not based on STM32 MCU).
Can someone please share some insights here as to how to overcome this problem. Your help is much appreciated.