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ADSP-SC589 USB Ports

Question asked by SHM@Nautel on Sep 23, 2016
Latest reply on Oct 3, 2016 by SHM@Nautel

I’m wondering if anyone out there has fully exercised the two USB ports on the SC589 yet? I have been able to use the OTG port under U-Boot to read a thumb drive and use a mouse but have not been able to get the second USB port working yet, and have not gotten either to work under Linux (but that could be a buildroot configuration error on my part).


One issue could be that the second port is not listed in the board DTS file. Looking at the file for the board, it appears that only one USB port is listed in there so I’m guessing a second entry is needed for the other port. Does the documentation for this entry exist somewhere?


The second issue, after looking at the schematics for the board, is that it appears that the 5V power for the second USB port is disabled based on the population of the resistors on the enable line. I suspect this puts the port into a peripheral mode since a host port is supposed to supply the 5V. Will enabling this power supply enable this USB port in host mode?


I’m wondering because we are trying to use the two USB ports in a design and I want to connect the second (non-OTG) port to a HUB chip. So I first want to try and get both USB ports working and talking to an external hub.


I also need to figure out if I need to connect the USB1_VBUS pin on the SC589 to a 5V source to tell it that there is a downstream port connected (the HUBs upstream port) or if the port can simply be turned on in software with register configurations. The documentation is not clear on the function of the USB1_VBUS pin and what it expects. It’s also listed as and InOut pin but I believe it is only an input.


Any clarification on this would be appreciated.