STM32F429 Discovery as USB Host. Problems enumerating Low-Speed Device over Full-Speed HUB.
Hello everyone,
I'm using the STM32F429 Discovery board as a USB Host. Using the ST Host Library I managed to get several different HID devices working (Full Speed and Low Speed).
I changed the Host Library so that it can handle multiple Devices. I also developed a HUB Class driver which is also working fine. My program is now able to work with an USB Hub, as long as I only connect full-speed devices to the HUB.
Since the Host and the HUB is working in Full-Speed I added the PREamble PID for communication with Low Speed devices. The weird thing is now that the enumeration of Low-Speed devices is only working about 50% of the time. Once the Low-Speed device is enumerated I can recieve as many interrupt inputs as I want without any issues. But the other 50% that I connect the Low-Speed device to my HUB the USB core state machine gets Stuck in the enumeration process.
I found similar topics in this forum that are describing the same problems such as:
https://community.st.com/s/question/0D50X00009XkiNNSAZ/stm32f217-usb-fs-host-mode-hub-problem
I also found a thread where an ST employe mentioned something about a hardware issue in the On chip PHY that might be responsible for this error. But I couldn't find any follow up on this:
as far as I know there is also no errata that describes this problem, yet.
I also found in the User Guide for the emUSB Host stack by segger a mention about this:
https://www.segger.com/downloads/emusb-host/UM10001 (19.3.2.2)
My question now is what is this all about? Is this a know issue? If so is there already an errata about this? If not does anyone know how I could try to work around this issue? And is this problem only occuring on the STMF429 or also on other Chips?