MultimodeRefDesign Firmware on NonNexus Devices

Technical discussions related to any XMOS development kit or reference design. Eg XK-1A, sliceKIT, etc.
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cloudline
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MultimodeRefDesign Firmware on NonNexus Devices

Post by cloudline »

Hi everyone. I am new to using XMOS.
I am in a project for universal phone dock, and we are referencing from the XMOS USB audio multimode dock (http://www.xmos.com/en/multimodedock).
We have created our custom board to run both iOS and Android USB audio streaming.
For the iOS part we are able to run the reference firmware smoothly.

For the Android device USB audio, I am having problems such that no audio streaming is started even though the Android phone has indicated it has connected to a USB device. We are using Samsung Galaxy Note2 and Samsung Galaxy S4 phones as the test android phones. We are using the "nexus7_ios_board" firmware from the "xmos_multifunction_audio" project firmware we got along with purchasing the XMOS multimode reference design board "XPCB-050-PACK-1V1". We would like to also note that we have connected the Android USB connector to be in OTG mode, as needed to have a USB host function for the Android phone. And we are using Android 4.1 and 4.2 OS.

We noticed that in the XMOS demo, you used a Nexus 7 tablet.
Does this mean that the XMOS firmware "nexus7_ios_board" works USB audio with Nexus devices only?
We would like to ask further if what specific Android devices did your reference firmware actually worked on?
Also, are there changes in firmware needed to make it work in other Android devices? We would like to ask guidance on how this can be done.

Hoping for your support and guidance.
Thank you!


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Ross
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Post by Ross »

My understanding of that demonstration is that the XMOS device operated as a host to the Android device. XMOS are currently investigating how USB Audio is best supported for Android devices - Typically Android USB Audio drivers seem to have restrictions regarding sample bit depth.
cloudline
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Post by cloudline »

Ross wrote:My understanding of that demonstration is that the XMOS device operated as a host to the Android device. XMOS are currently investigating how USB Audio is best supported for Android devices - Typically Android USB Audio drivers seem to have restrictions regarding sample bit depth.
So you mean the android device is the accessory and not the host right? Does this mean that OTG connection is not needed, unlike most Android DACs?
Really appreciate it if XMOS can be easily ported to provide USB audio with Android devices.
Can you please confirm if the demo firmware has been tested for other android device models like Samsung and HTC phones?
Thank you
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sethu_jangala
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Post by sethu_jangala »

The "xmos_multifunction_audio" firmware and the "nexus7_ios_board" application reference was developed as a demonstration only. It has not been maintained since the original demonstration.
This particular Android demonstration used the Android AOA framework (where XMOS is the USB host and the Android device is the USB XMOS device), which is the official way to extract USB audio from an Android device.
As it was a demonstration only, the code was likely tested with that particular Nexus7 tablet only.
XMOS are not maintaining this particular firmware release so unfortunately is not able to offer support.

As a general comment, XMOS is currently assessing how to best support operation with Android devices.
Options include:
- AOA. Android is a USB device. Official method of extracting USB audio from an Android device so widely supported. But limited audio capabilities.
- Android host. Android is the USB host. Requires phone vendor to implement UAC support as a USB host, so not supported by all Android devices. But where supported offers wider audio capabilities.
XMOS do not have a timescale for any of this activity at this point.
cloudline
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Post by cloudline »

Thanks Ross and Sethu for your comments
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