AnsweredAssumed Answered

usb hangs: stm32f4

Question asked by mark.s on Jan 31, 2014
Latest reply on Feb 12, 2016 by h..dino

I am implementing a CDC USB device using the STM32f4 and STM USB libraries.

What I am finding is that after sending a number of multi-byte packets from the PC > STM32 the OUT pipe effectively hangs and I receive no further data from the PC. I can see the packet sent to the device (software packet sniffer) but I receive no interrupt on the STM32 to indicate that an OUT packet has been received.

BTW I'm not sending huge buffers of data, I can make it go wrong by sending 4 byte sequences in real term. After a random number of goes it no longer receives packets. If I send single byte packets it just won't go wrong using real term.

I have tested that I can continually send IN packets to the PC even when the OUT pipe has hung. It's almost as though an interrupt flag hasn't been cleared or something.

Has anyone else experienced this? Seems like a strange timing issue to me.

I'll continue to delve...