USB Host and Accessory Mode

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hi guys,

i tried reading up on usb host and accessory mode but there some part that i do not understand.

In accessory mode the Android phone or tablet acts as the USB Device and the accessory acts as the USB Host. This means that the accessory is the bus master and provides power.

i am wondering if i using a samsung galaxy s2 (andorid 2.3.4) which will support usb accessory mode, and use a OTG cable and connect to a usb flashdrive, how come it work? i dun tink the usb flashdrive are powering the bus?

please enlighten me. thanks everyone!

anyone can help?

The Galaxy S2 has both USB_OTG and accessory mode.
USB_OTG is changing between USB host and device, and accessory mode is a special role under being a device.

                usb host
USB-OTG<
                usb device< acting as a flash drive when connected to a pc,
                                 android accessory mode

While being in host mode a real and full USB_OTG-device powers the other device. However, the required amperage in the specification is only 8 mA...nearly nothing. This is enough for a flash drive, but not for other things like mice or keyboards. Than you will need a powered hub, or an y-cable might work.

Hope that answered your questions?!? Also, have a look at youtube, there are videos with the GS2 and keyboards and mice.

hi,

thank a lot for your reply.

how about samsung galaxy S2 that is running on android 2.3.4?

if i not wrong, usb host is only supported in android 3.1 onward. so in android 2.3.4 it is running in accessory mode.

since it running in accessory mode, this mean the accessory will be the USB host and the galaxy S2 will be the USB device. so the powering of the bus will be by the accessory. galaxy S2 support reading of flashdrive in android 2.3.4. if i am connecting the flashdrive to the galaxy S2, who is powering the bus? i know it will be the galaxy S2 but why is this so? arent in accessory mode, the accessory should be powering the bus instead?

Thanks!

Samsung Galaxy S2 and Google ADK

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please help with google and arduino mega adk.

unable to connect with samsung galaxy s2