In our DM368 based board I have to work with multiple USB devices simultaneously. All these USB devices are connected to the processor through USB HUB. It is not enough HCD controller end points – so I need to access multiple devices bulk endpoints though a single HCD endpoint. I set a HOST_RXINTERVAL to 4 and I expect to get interrupt after 4 unsuccessful NAK-s but I never got any interrupt. On USB analyzer I can see multiple NAK-s coming from the device end-point to HCD.
In Linux driver I found next comment:
/* Enable bulk RX/TX NAK timeout scheme when bulk requests are
* multiplexed. This scheme doen't work in high speed to full
* speed scenario as NAK interrupts are not coming from a
* full speed device connected to a high speed device…..
I did not found any mention of this limitation in TI documentation.
Questions – 1.Does DM368 USB controller has this limitation and where I cen read about it? 2. Is it any known workarounds?