Hi There I am too trying to make the mini usb port to work as a host.
I am trying to scan the expansion port signals it seams like none of the pins offers direct access to the processor vbus signal. Should I do this with some software? If with software; what time should it work to enable/disable the volt? And should it listen to the signal all the time or just during the port initialization stage? Best Regards Mahammad On Wednesday, August 21, 2013 4:38:47 AM UTC+2, AndrewTaneGlen wrote: > > Understood. Thanks for taking the time to clear that up for me. > > > Andy. > > On Wednesday, 21 August 2013 14:36:59 UTC+12, Gerald wrote: >> >> Yes, that is what I am saying. I did a design where the 5V was always >> there. It din't work. I had to add a power switch like I did on the BBB >> design. >> >> >> Gerald >> >> >> On Tue, Aug 20, 2013 at 9:33 PM, AndrewTaneGlen <[email protected]>wrote: >> >>> Thanks Gerald, >>> >>> That was one thing I was not absolutely clear on. The TRM has the >>> following passage concerning USB power control: >>> >>> "*When any of the USB controllers assumes the role of a host, the USB >>> is required to supply a 5V power* >>> *source to an attached device through its VBUS line. In order to achieve >>> this task, the USB controller* >>> *requires the use of an external power logic (or charge pump) capable of >>> sourcing 5V power. A* >>> *USB_DRVVBUS is used as a control signal to enable/disable this external >>> power logic to either source or* >>> *disable power on the VBUS line. The control on the USB_DRVVBUS is >>> automatic and is handled by the* >>> *USB controller.*" (AM335X TRM, pg. 1697) >>> >>> So are you saying, in addition to the above, that the USB port must be >>> in control of the VBUS enable - assumedly detecting the voltage as off when >>> disabled, and on when enabled, with specific timing requirements around >>> these edges - so that there is no way to simply have the 5V there the whole >>> time? >>> >>> If this is the case I guess there is a chance that I could add some kind >>> of gpio control through the expansion header to enable/disable the 5V rail >>> as and when required (or I could just modify the board - but I'm trying to >>> avoid this and be able to just plug my clean BBB into my horrible looking >>> base board...) >>> >>> >>> Regards, >>> Andy. >>> >>> On Wednesday, 21 August 2013 14:20:08 UTC+12, Gerald wrote: >>> >>>> Like the fact that the processor needs to see the 5V on >>>> the processor pin when it turns on the 5V? >>>> >>>> Take a look at the host port design. Both ports are actually OTG ports >>>> by design. To make the state machine in the HW function as a host, you >>>> need >>>> to make it work like the other OTG port, the one we call the Host port, >>>> which is configured for host.. >>>> >>>> >>>> Gerald >>>> >>>> >>>> >>>> On Tue, Aug 20, 2013 at 9:12 PM, AndrewTaneGlen >>>> <[email protected]>wrote: >>>> >>>>> Hi All, >>>>> >>>>> I've been playing around with getting the mini-USB pc connector to >>>>> function as a second USB host (I'm using RCN's Ubuntu, Raring, but I'd >>>>> assume this would apply to Angstrom as well). There is a post here >>>>> http://pansenti.wordpress.com/2013/05/27/ >>>>> beaglebone-black-with-two-usb-host-ports-it-can-be-done-but- >>>>> its-not-easy/ decribing how to do this with some hardware >>>>> modifications, but looking at the AM335x technical reference manual it >>>>> looks like I should be able to set USB Port 0 to function as a host >>>>> through >>>>> software alone (i.e. without needing to ground the USB ID pin, or to >>>>> modify >>>>> anything else on the board). >>>>> >>>>> So what I have done so far is modify the 'am33xx.dtsi' file under the >>>>> 'usb_otg_hs' section, and change the item 'port0-mode = <3>' to >>>>> 'port0-mode >>>>> = <1>', which, according to 'am33xx-usb.txt' in the device tree >>>>> documentation, should force this port to function in Host mode. >>>>> >>>>> I then had a look through menu config, in the 'Device Drivers' -> 'USB >>>>> Support' section and there didn't seem to be anything specifically >>>>> relating >>>>> to setting the mode of any particular usb port, so I left all of this >>>>> unchanged. >>>>> >>>>> Upon booting I can see that whereas previously I would get the >>>>> following wit regards to USB0: >>>>> >>>>> musb-hdrc musb-hdrc.0.auto: *** mode=3 >>>>> >>>>> I now get >>>>> >>>>> musb-hdrc musb-hdrc.0.auto: *** mode=1 >>>>> >>>>> This would appear to indicate that my device tree change had been >>>>> successfully applied, and the initialisation of USB port0 now looks >>>>> identical to that of port1. whereas previously they were quite different. >>>>> >>>>> I then customised my USB cable to have an external 5V feed (wired to >>>>> SYS_5V on the expansion header) and added a female-female USB A adaptor >>>>> to >>>>> give me a host socket. >>>>> >>>>> However, it doesn't work. >>>>> >>>>> I have checked the power rail and can see 5V on R159 on the bottom of >>>>> the BBB and I have double checked that the comms wires are the correct >>>>> polarity, and everything buzzes out as expected. >>>>> >>>>> The device boots, and I can SSH into it. Plugging a memory stick into >>>>> the standard usb host plug causes messages related to detecting and >>>>> attaching a disk, but when I plug the same disk into the modified >>>>> connector >>>>> assembly I get noting at all. >>>>> >>>>> Taking out my change to the device tree returns the mini-USB >>>>> connection to normal functionality, i.e. providing a network connection, >>>>> so >>>>> it would appear that the hardware is all still in good working order. >>>>> >>>>> So I'm wonder if anyone else has had luck using the USB OTG connection >>>>> in host mode - without making any hardware modifications to the board? I >>>>> all looks like it should work, so I'm guessing I've missed something >>>>> fairly >>>>> basic. >>>>> >>>>> >>>>> Regards, >>>>> Andrew Glen. >>>>> >>>>> -- >>>>> For more options, visit http://beagleboard.org/discuss >>>>> --- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "BeagleBoard" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to [email protected]. >>>>> >>>>> For more options, visit https://groups.google.com/groups/opt_out. >>>>> >>>> >>>> -- >>> For more options, visit http://beagleboard.org/discuss >>> --- >>> You received this message because you are subscribed to the Google >>> Groups "BeagleBoard" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> For more options, visit https://groups.google.com/groups/opt_out. >>> >> >> -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. 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