Android Open Accessory Development Kit

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Android Open Accessory Development Kit

(8 posts) (3 voices)

Started 4 years ago by gbulmer
Latest reply from gbulmer

gbulmer
Moderator

Folks may have seen the new support in Android for USB-attached gizmo's http://developer.android.com/guide/topics/usb/adk.html
and the Arduino-based hardware http://arduino.cc/blog/2011/05/10/google-launches-android-open-accessory-development-kit-based-on-arduino/

This appears in Android 3.1, but they say it is back-ported to Android 2.3.4

The key is
... When an Android-powered powered device is in accessory mode, the connected accessory acts as the USB host ...

It looks like an STM32F105-based board would be great for this.
Has anyone tried to develop a USB host using an STM32F105?
Is there a design folks would start from?

Posted 4 years ago #
x893
Member

I modify maple board for STM32F105 and use it in device and host mode. Now i use it with flash, wi-fi and bluetooth adapters. But i havn't android device so can't check communication. Also you can add USB shild (based on MAX3421 chip) to standard Maple and port arduino code to it (not a hard).

Posted 4 years ago #
x893
Member

Also you can use Android 3.1 device with builtin USB support and standard Maple.

Posted 4 years ago #
gbulmer
Moderator

I modify maple board for STM32F105 and use it in device and host mode.

Are you sharing the schematic and code? If you are, would you please post a link?

Also you can use Android 3.1 device with builtin USB support and standard Maple.

Would you point me at the place that explains this? I had assumed that to be the case, but I've failed to find it.
Edit: found it:
http://developer.android.com/guide/topics/usb/host.html

The link http://developer.android.com/guide/topics/usb/adk.html seems very clear that the "Android powered-device" becomes the USB device, and the "Android USB accessory" is the USB host.

Posted 4 years ago #
x893
Member

You can see and download files from here (also support STM32F2XX)
http://akb77.com/g/stm32/stm32-arduino/

Posted 4 years ago #
poslathian
LeafLabs

Does anyone here know what it would take to build an ADB interface on Maple to android. I gather this requires USB host as x893 mentioned, but if you know more about it please describe.

Posted 4 years ago #
gbulmer
Moderator

poslathian - There are two ways to communicate with an Android device, and both Android as USB host, and Android as USB device exist:
http://developer.android.com/guide/topics/usb/index.html

If using an Android 3.1 devices with USB host controller is okay, then
http://developer.android.com/guide/topics/usb/host.html
looks pretty straightforward.
It looks possible to just 'chat' to an endpoint on a USB device. In theory, an Android 3.1 device with USB host controller would 'just work' (TM) with Maple.

If you want some gizmo which will support more Android devices (i.e. earlier than Android 3.1, or devices without USB host controllers), then that gizmo must be a USB host.
In this case, the Android device looks like a USB device and the gizmo is a "USB Accessory":
http://developer.android.com/guide/topics/usb/accessory.html

As x893 says, this can't be too hard because the the device that google has demo'd appears to be a merge of an Arduino and a Circuits@Home USB host shield:
http://developer.android.com/guide/topics/usb/adk.html

All of the code and CAD are available in the "ADK package download"

The quickest way to get something working as a USB host might be to get a Circuits@Home USB host shield and port the code.

I googled around, and there are several existing Android devices which have had the USB controller hardware for more than a year (HTC Hero and Motorola Droid):
http://adq.livejournal.com/95689.html
http://www.tombom.co.uk/blog/?p=124
Some of the chipsets that are used by the smartphone makers have USB host controllers built in. So the restriction to Android devices which run Android 3.1 and have USB host controllers might not be as big a constraint as one might imagine.

I think I'd prefer to start at Android 3.1, and try talking directly to a Maple first as that should be software only, but I have very little time for the next few weeks :-(
Oh, and I haven't got an Android 3.1 device (yet :-)

This is very close to my core interest, so I will try to do something. This would solve a bunch of issues for my interests.

Edit: Here is an article about the changes in Android 3.1 which should show up on a Motorola Xoom:
http://www.fonehome.co.uk/2011/05/12/android-3-1-update-detailed/
It specifically says that it will act as a USB host, and devices will show up in the same way as they do on a PC. The demo is a "wired Xbox 360 pad".

I'll give it a couple of weeks for folks to get their hands on this stuff, and if it seems okay, maybe I'll need a Xoom?

Posted 4 years ago #
gbulmer
Moderator

Dean Camera (creator of LUFA) posted:
http://groups.google.com/group/lufa-support/browse_thread/thread/6276262ccfa59c6a?hl=en

It's very rough, but if anyone with an Android phone could try this
out:
https://code.google.com/p/lufa-lib/source/browse/trunk#trunk%2FDemos%...
It should connect to the device, correctly switch it into accessory
mode, then stream out bytes sent to the LEDs on the board. If this
works at all, I'll make a proper class driver for it, and add in all
the missing features.

Maybe it is time to talk to Dean and figure out how to port LUFA to Maple, and get all those useful USB devices?
He did write a while ago (to me) about making changes to LUFA which would make it easier to port to other MCU's (than ATmega), but I don't know if he has done that.

Posted 4 years ago #

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