android 3.1 usb host

8/3/2019 Android 3.1 USB Host

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USBUniversal Serial Bus (USB) is a serial bus standard to interface devices. USBwas designed to allow many peripherals to be connected using a singlestandardized interface socket and to improve the plug-and-play capabilities by

allowing devices to be connected and disconnected without rebooting thecomputer (hot swapping). Other convenient features include providing powerto low-consumption devices without the need for an external power supplyand allowing many devices to be used without requiring manufacturerspecific, individual device drivers to be installed.http://en.wikipedia.org/wiki/USBA nice story about the development of the USB interface: The D/A diaries: Apersonal memoir of engineering heartache and triumph by Hitoshi Kondoh.USB is a computer bus like any other but for some reason it inspires people tomake all kind of funny products.

USB wedding ring

Introduction

USB audio is very popular.One of the reasons is that USB audio is part of the USB standard and as aconsequence native mode drivers are available in all the popular OS (Win,OSX and Linux).Connecting a USB audio device is a matter of plug&play.USB audio is a flexible solution as any PC offers USB.

If you use a laptop this is probably the way to go if you want to improve on theon-board sound card.The audio is routed to the USB.This is a matter of choosing the USB audio device in your media player.The on-board sound card is bypassed; in fact you dont need a sound card atall.The USB audio device is your (outboard) sound card.Today the resolution of USB audio standard ranges from 16 bit/ 32 kHz to 32bit/ 384 kHz.

A lot of DACs are still limited to 16 bit/ 48 kHz max.
http://en.wikipedia.org/wiki/USBhttp://www.planetanalog.com/showArticle.jhtml?articleID=12801995http://www.planetanalog.com/showArticle.jhtml?articleID=12801995http://www.dialog05.com/http://en.wikipedia.org/wiki/USBhttp://www.planetanalog.com/showArticle.jhtml?articleID=12801995http://www.planetanalog.com/showArticle.jhtml?articleID=12801995


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The data transfer from the PC to the DAC can be done in adaptive or inasynchronous mode.In adaptive mode the DAC adjust its timing to the rate the data is pouring in.In asynchronous mode the DAC keeps its timing constant and controls theamount of data send by the PC. By design asynchronous mode eliminates

input jitter.

Resolution

A lot of people think USB audio is limited to 16 bits / 48 kHz max.A lot of (cheap and sometimes not so cheap) USB DACs are indeed limited tothis resolution.This is because the manufacturer decided to use a simple and cheap of theshelf hardware solution.Another common misunderstanding is the specification of the bus (USB 1,2 or3) and the USB audio standard (1 or 2).

USB Audio Class 1 standard (1998)This standard allows for 24 bits / 96 kHz max.The standard itself doesn't impose any limitation on sample rate.Class 1 is tied to USB 1 Full Speed = 12 MHz

Every millisecond a package is send.Maximum package size is 1024 bytes.2 channel * 24 bit * 96000 Hz sample rate= 4608000 bits/s or 576 Byte/msThis fits in the 1024 byte limit.Any higher sample rate e.g. 172 kHz needs 1056 bytes so in excess of themaximum package size.All operating systems (Win, OSX, and Linux) support USB Audio Class 1natively.This means you dont need to install drivers, it is plug&play.All support 2 channel audio with 24 bit words and 96 kHz sample rate

USB Audio Class 2 standard (2009)

It is downwards compatible with class 1.USB Audio Class 2 additionally supports 24 and 32 bit and all commonsample rates.Class 2 uses High Speed (480 MHz). This requires USB 2 or 3.

As the data rate of High Speed is 40 X Full speed, recording a 60 channelusing 24 bits at 96 kHz (132 Mbit/s) is not a problem.

Drivers

From mid-2010 on USB audio class 2 drivers are available in OSX 10.6.4 andLinux.Both support sample rates up to 384 kHz.It is unclear if Microsoft is going to support USB Audio 2.You need a third party USB class 2 driver on Windows.Companies like Thesycon orCentrance have developed a USB Class 2Audio driver for Windows.

Using High Speed USB for playback there are no limits in resolution.
http://www.usbdacs.com/hs24192/hs24192.htmlhttp://centrance.com/downloads/ud/http://www.usbdacs.com/hs24192/hs24192.htmlhttp://centrance.com/downloads/ud/


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USB Speed

High Speed - 480 Mb/s with a data signalling tolerance of 500ppm (USB 2)

Full Speed - 12 Mb/s with a data signalling tolerance of 0.25% or 2,500ppm.(USB 1&2)

Low Speed - 1.5Mbits/s with a data signalling tolerance of 1.5% or15,000ppm (USB 1&2)

USB receivers

The data send over the USB must be transformed to a format a DAC (the chipdoing the DA conversion) does understand. This can be SPDIF or I2S.This is the task of the receiver chip.Adaptive mode 16 bit units often use the Cmedia or TI (PCM270x) based chip

sets. These are not programmable and usually only support 16 bit and 32,44.1, 48 kHz sample rate.An example of how this chip-set performs compared with asynchronous USBcan be foundbelow.24 bit adaptive mode DACs needs a programmable design (TAS1020 or otherUSB Audio Controller).This chip enables 24 bit/ 96 kHz over USB.Chips like the TAS1020 are limited to full speed.You can't do high speed as needed for USB audio class 2.

96 kHz is the upper limit when using native mode USB Audio Class 1 drivers.A USB audio class 2 or a custom driver is needed to run 176/ 192 kHz andhigher.The XMOS chipset is often used.XMOS
http://thewelltemperedcomputer.com/KB/USB.html#AdaptiveAsynchttp://www.xmos.com/products/development-kits/usbaudio2http://thewelltemperedcomputer.com/KB/USB.html#AdaptiveAsynchttp://www.xmos.com/products/development-kits/usbaudio2


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XS1-L1 USB Audio 2.0

500 MIPS, 8 threads, XS1-L1 processor

2 Channel analog input

2 Channel analog output

USB 2.0 high speed interface - supports multiple 24 bit, 192kHz channels withextremely low latency (3ms round trip)

Plug-and-play with Audio Class 2.0 enabled computers (native Mac OSXsupport,Windows drivers available)

Audio Class 1.0 compliant - native Mac OSX and Windows support

Asynchronous clocking - complete control of the audio master clock

S/PDIF (TOSLINK) output

Basically a USB to Toslink converter.

Transfer modes

Data is exchanged over USB using one of the four possible modes:


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Control Transfers: command and status operations,

Interrupt Transfers: device requires the attention of the host

Bulk Transfers: large volumes of data like print jobs

Isochronous Transfers: time sensitive information, such as an audio or videostream

o Guaranteed access to USB bandwidth.

o Bounded latency.

o Stream Pipe - Unidirectional

o Error detection via CRC, but no retry or guarantee of delivery.

o Full & high speed modes only

Transfer modes explained in detail.

Synchronous, adaptive and asynchronous synchronization

When the computer sends the audio stream to an USB port, if first reads thedata from the hard disk and caches blocks of the data in memory.It is then spooled from memory to the output port in a continuous stream(Isochronous mode).Data is sent out in frames every millisecond.This happens whether there is any data in them or not.The rate at which the frames go out is determined by a oscillator driving theUSB bus.

This rate is independent of everything else going on in the PC.In principle this guarantees a constant flow of the frames.In practice the frames might not be filled properly with data because someprogram simply hogs the CPU or the PCI.Anti virus polling the internet at high priority are a well known example.Isochronous transfer can be done with three possible types of synchronizationmodes in the USB audio device.

Synchronous

The clock driving the DAC is directly derived from the 1 kHz frame rate.

This mode was used by the early USB audio devices.They were limited to 48 kHz and pretty jittery.

Adaptive

In this mode the clock comes from a separate clock.A control circuit (sample rate guesser) measures the average rate of the datacoming over the bus and adjusts the clock to match that.Since the clock is not directly derived from a bus signal it is far less sensitiveto bus jitter than synchronous mode, but what is going on the bus still canaffect it.Its still generated by a PLL that takes its control from the circuits that see the

jitter on the bus.This is the mode that most USB audio devices use today.
http://www.beyondlogic.org/usbnutshell/usb4.htmhttp://www.beyondlogic.org/usbnutshell/usb4.htm


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Asynchronous

In this mode an external clock is used to clock the data out of the buffer and afeedback stream is setup to tell the host how fast to send the data. A controlcircuit monitors the status of the buffer and tells the host to speed up if thebuffer is getting too empty or slow down if its getting too full.Since the readout clock is not dependent on anything going on with the bus, itcan be fed directly from a low jitter oscillator, no PLL need apply.This mode can be made to be very insensitive to bus jitter.

The warm reception in the audiophile world of asynchronous USB asdeveloped and promoted by Wavelength inspired other brands toofferasynchronous USB DACs .Asynchronous mode is not better by design but by implementation becauseyou can implement a top quality (low jitter) clock in the DAC.There is actually a good example of this case of its the implementation of theclock thats important, not the asyncness itself that is important. The recentinexpensive Musiland devices use an asynchronous protocol but then use afrequency synthesizer to generate the local clock rather than use a fixedfrequency oscillator. The result is jitter that is actually worse than some of thebetter adaptive implementations!John SwensonNot everybody agree that asynchronous is better.Centrance, manufacturer of adaptive mode solutions, is one of them.Some manufacturers may lead you to believe that Asynchronous USBtransfers are superior to Adaptive USB transfers. This no more true thansaying that you "must" hold the fork in your left hand. If you know what you

are doing, you will feed yourself with either hand.Michael Goodman, Chief Product Architect
http://thewelltemperedcomputer.com/HW/USB_DAC.htmhttp://www.head-fi.org/forum/thread/493152/low-jitter-usb-dan-lavry-michael-goodman-adaptive-asynchronoushttp://centrance.com/products/dacport/http://www.usbdacs.com/Concept/Concept.htmlhttp://www.usbdacs.com/Concept/Concept.htmlhttp://thewelltemperedcomputer.com/HW/USB_DAC.htmhttp://www.head-fi.org/forum/thread/493152/low-jitter-usb-dan-lavry-michael-goodman-adaptive-asynchronoushttp://centrance.com/products/dacport/


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Async USB provides a simpler way to implement a low jitter DAC relative toadaptive mode USB. For the cost of a small number of lines of firmware code,you reduce the amount and complexity hardware needed and potentiallyreduce the cost of the hardware needed for a high quality result. Most thinkingengineers appreciate simplicity and the potential for low cost designs that

deliver the goods.You can find plenty of bovine excrement in the marketing of all kinds of high-end gear. Marketing products using buzz words without supporting detail ortest results works when the audience is technically ignorant.Old Listener

Measurement

JimLesurfdid a nice experiment.He measured the analog out of a DAC Magic when feed by its own adaptivemode USB and by a asynchronous USB to SPDIF converter (Halide).
http://www.whatsbestforum.com/showthread.php?1201-Music-Server-Project&p=19380#post19380http://www.audiomisc.co.uk/Linux/Sound3/TimeForChange.htmlhttp://www.whatsbestforum.com/showthread.php?1201-Music-Server-Project&p=19380#post19380http://www.audiomisc.co.uk/Linux/Sound3/TimeForChange.html


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The differences between adaptive (USB direct) and asynchronous (Halide)are clear.According to the author not only measurable but also audible.[5]

USB cables

Cable length between full speed devices is limited to 5 meters. For a lowspeed device the limit is 3 meters.As the signal degrades proportional to the length of the cable, a short cable isoften recommended.Other says this can put a source of RFI (the PC) to close to the USB-DAC.

Audiophile USB cables

USB audio is gaining momentum.Like analogue interconnects, now you have audiophile USB cables.Audiophile USB cables are as controversial as analogue interconnects.It is hard to imagine that one cable deliver better bits than the other but jittercomes to cable manufacturers rescue.

The Limitations of digital audio processors and cables create timing errorsknown as jitter, which remove portions of the audio signal and replace themwith noise and distortion. Cables tend to round off the square waveforms ofthe signal, making them less clear to the processor, thus increasing jitter. Thisrounding effect varies greatly among cables and a truly superior digital audiocable can make great improvements in sound quality.http://www.wireworldcable.com/categories/usb_cables.htmlAnother manufacturer talking some marketing bull shit?They do have a point.Digital is indeed sending fully analogue electrons over a wire.

And indeed, the block pulse degrades with the length.A good digital cable is one who minimizes this degradation.
http://thewelltemperedcomputer.com/KB/USB.html#JimLesurfhttp://thewelltemperedcomputer.com/KB/USB.html#JimLesurfhttp://www.wireworldcable.com/categories/usb_cables.htmlhttp://thewelltemperedcomputer.com/KB/USB.html#JimLesurfhttp://www.wireworldcable.com/categories/usb_cables.html


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This is an easy test.Connect your high speed USB device, e.g. a hard disk using your audiophilegrade USB cable. If hi-speed mode (480 Mbps instead of 12 Mbps, the oldUSB 1 standard) fails, it is a bad DIY digital cable not even compliant withUSB 2 standards.

More details can be found here.

Configuring

A clear and well written step by step guide to setup and USB DAC using XP,Vista or OSX can be found at the Ayre website.Setup forWin7.Setup forVista.

Drop out.

Some users complain about drop outs when playing USB audio.

This might be due to different devices sharing the same USB-Hub.If your audio and your graphics card are on the same hub, the bandwidthrequired by the graphics might cause the audio to stutter.Anti-virus programs polling the internet with high priority might interrupt theaudio too.

Trouble shooting

Using another port for your audio might cure the problem if the new port it isattached to another hub. Use the windows device manager and see if you can findan usb-controller using an IRQ not used by other devices.

Open the Task Manageror the Resource Monitorand check for processespeaking or doing a lot of I/O

Run a program like DPC Latency Checker

A simple solution is to buy a PCI to USB card. As it is PCI it gets 1 exclusiveinterrupt. Use this one for USB audio only and the audio device can get 100%bandwidth.More:http://www.audioasylum.com/cgi/vt.mpl?f=pcaudio&m=33658http://www.audioasylum.com/cgi/vt.mpl?f=pcaudio&m=33930http://www.m-audio.com/index.php?do=support.faq&ID=de0c17eee57afeeba3978a213b6d86ac

References

1. Universal Serial Bus - usb.org

2. USB audio spec and jitter- John Swenson

3. How USB Works - Tech-Pro.net

4. USB in a NutShell - Byond Logic

5. Time for a change? - Jim Lesurf
http://www.audioasylum.com/cgi/vt.mpl?f=pcaudio&m=65850http://www.ayre.com/usb.htmhttp://thewelltemperedcomputer.com/SW/Windows/Win7/USBDAC.htmhttp://thewelltemperedcomputer.com/SW/VistaTweak.htmhttp://thewelltemperedcomputer.com/SW/Windows/Win7/USBDAC.htm#USBPorthttp://thewelltemperedcomputer.com/SW/AudioTools/TroubleShooting.htm#DPCLatencyCheckerhttp://www.audioasylum.com/cgi/vt.mpl?f=pcaudio&m=33658http://www.audioasylum.com/cgi/vt.mpl?f=pcaudio&m=33930http://www.m-audio.com/index.php?do=support.faq&ID=de0c17eee57afeeba3978a213b6d86achttp://www.m-audio.com/index.php?do=support.faq&ID=de0c17eee57afeeba3978a213b6d86achttp://www.usb.org/http://www.audioasylum.com/forums/pcaudio/messages/7719.htmlhttp://www.tech-pro.net/intro_usb.htmlhttp://www.beyondlogic.org/usbnutshell/usb1.htmhttp://www.beyondlogic.org/usbnutshell/usb1.htmhttp://www.audiomisc.co.uk/Linux/Sound3/TimeForChange.htmlhttp://www.audioasylum.com/cgi/vt.mpl?f=pcaudio&m=65850http://www.ayre.com/usb.htmhttp://thewelltemperedcomputer.com/SW/Windows/Win7/USBDAC.htmhttp://thewelltemperedcomputer.com/SW/VistaTweak.htmhttp://thewelltemperedcomputer.com/SW/Windows/Win7/USBDAC.htm#USBPorthttp://thewelltemperedcomputer.com/SW/AudioTools/TroubleShooting.htm#DPCLatencyCheckerhttp://www.audioasylum.com/cgi/vt.mpl?f=pcaudio&m=33658http://www.audioasylum.com/cgi/vt.mpl?f=pcaudio&m=33930http://www.m-audio.com/index.php?do=support.faq&ID=de0c17eee57afeeba3978a213b6d86achttp://www.m-audio.com/index.php?do=support.faq&ID=de0c17eee57afeeba3978a213b6d86achttp://www.usb.org/http://www.audioasylum.com/forums/pcaudio/messages/7719.htmlhttp://www.tech-pro.net/intro_usb.htmlhttp://www.beyondlogic.org/usbnutshell/usb1.htmhttp://www.audiomisc.co.uk/Linux/Sound3/TimeForChange.html


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6. Universal Serial Bus Device Class Definition for Audio Devices 1 - UniversalSerial Bus (1998)

7. Universal Serial Bus Device Class Definition for Audio Devices 2 - UniversalSerial Bus (2006)

8. USB audio standards - Computer Audio Asylum

Vincent Kars May 2011http://thewelltemperedcomputer.com/KB/USB.html

USB AUDIO - SYNCHRONOUS/ASYNCHRONOUSDATA TRANSFER

There are a couple of methods for sending audiodata over an usb cable.Here's an explanation of the principles behind them and the advantagesof one over another.

Synchronous USB connections use a one way digital connection for music replay

and are considered the worst type of connection for audio purposes

Adaptive mode is a little smarter. It asesses the amount of data in the frameand adjusts that dac's clock-timing to it.Asynchronous mode is technically most advanced in that it has a feedback loop

so that the amount of data in the frame can be controlled.

Conventional USB connections use a one way digital connection for music replayand use the computer's bus frame rate as source for the clock which is less stablethan a fixed one. A computer sadly cannot maintain perfect timing of the datasent via USB. For adaptive mode, the receiving chip adapts to this drifting signalby re-adjusting its own frequency every milisecond to match the incoming

frequency. This is already considered better. The downside of both methods isthat they tend to cause high levels of jitter. On top of this, the computer's clock is

not as stable (powerline fluctuations/RF pollution) as you would like for highendaudio purposes.
http://www.usb.org/developers/devclass_docs/audio10.pdfhttp://www.usb.org/developers/devclass_docs/Audio2.0_final.ziphttp://www.audioasylum.com/cgi/vt.mpl?f=pcaudio&m=89121mailto:[email protected]://thewelltemperedcomputer.com/KB/USB.htmlhttp://gizmodo.com/5305109/glowing-vacuum-tube-is-actually-a-usb-sound-cardhttp://www.usb.org/developers/devclass_docs/audio10.pdfhttp://www.usb.org/developers/devclass_docs/Audio2.0_final.ziphttp://www.audioasylum.com/cgi/vt.mpl?f=pcaudio&m=89121mailto:[email protected]://thewelltemperedcomputer.com/KB/USB.html


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Asynchronous USB (not to be confused with asynchronous samplerateconversion) uses a clock housed near the dac (usually in the external dac'scasing) and allows it to drive the converter directly, thereby not relying on theinstable computer's clock. Well, someone who is technically more adept at thismatter than me informed me that this is still not entirely true as the interface or

dac is still somewhat dependent upon the stability of the PC's bus clock. It iscalled asychronous because the dac's master clock isn't synchronized directly toany clocks within the computer. Instead, the dac is controlled by a (potentially

high-precision) fixed-frequency clock. This clock controls the datastream from thecomputer to a buffer near the DA converter.

A few examples:Ayre QB-9 = asyncDCS Scarlatti upsampler = asyncPS audio PWD = synchronous (adaptive) (but very well implemented)

M2Tech HiFace = asyncM2Tech HiFace EVO = async

Arcam rDAC = async

The thing is: Asynchronous USB data transfer doesn't guarantee perfect sound.Well, technically speaking, it does. But bit-perfect transfer doesn'tguarantee enjoyable sound. When using a PC as source, having very precise, verycorrect sound can be too much of a good thing if the source computer alreadysounds thin or when the rest of your system tends to the overanalytical. Having

all the bits in place is a good starting point, but many tests I've done have shownthat extremely precise dacs can be very unforgiving and too-controlled sounding,

while other dacs can be extremely musical. But what constitutes musical? This issomething that everyone has to decide for him or herself but my point is that

what you find sounding good doesn't neccesarily have to measure well. Thissounds controversial, I know. Of course it is best to use accurate applications onthe computer and also try to keep the data transfer as integer as possible. Butthis would lead to the best sound only if everything else in the system is carefullymatched. For example: on my full size PC, I like to use kernel streaming. Itprovides the best soundquality in my system. But when I use the Macbook, I

prefer iTunes without additions such as Amarra, simply because the Macbook, forwhatever reason, sounds very grey, flat, undimensional and technical. In my

opinion, using bit-perfect transfer (for example by means of Amarra) pushes thisalready lean and mean sound over the edge.

Compare it with the analog, physical world. If you were to assemble a systembased solely on specs, chances are that it will end up sounding very mediocre.

Use your ears instead, swap some cables, try a different rack, add componentfeet etcetera and you will effectively have coloured the system to match yourtaste or compensate for its weaknesses. In the computer world it is not muchdifferent.

The bottom line? Use your ears, not only your mind, and listen to thecomputer/transport/interface/dac of your choice and don't let the technicalmumbo jumbo get too much in the way!

http://www.hifi-advice.com/USB-synchronous-asynchronous-info.html
http://www.hifi-advice.com/USB-synchronous-asynchronous-info.htmlhttp://www.hifi-advice.com/USB-synchronous-asynchronous-info.html


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AndroidPlatformUpdates

Firstup isthe update to Honecomb from 3.0 to 3.1. Theupdate, which is being pushed out today

to Motorola Xooms on Verizon, includes a number of changes and optimizations, including an improved

task switcher, resizable widgets, UI improvements, and USBhost and accessorysupport.

USBhost modesupportis a huge step forwards for makingAndroida versatileplatform, as itenables Android devices to connect to peripherals like mice, keyboards, mass storage devices, digital

cameras, audio devices, hubs, and more.USB host mode also enables gamepad and joystick support,

including PS3 and Xbox 360 wired controllers,USB Logitech gamepads, fight sticks, and car controllers.

Almost anything that would otherwise present itself as aUSB accessory when connected to a PCwill

work with Androidtablets. Going forwards, it's clear that Android 3.1 could quickly become a gaming

platform on its own when coupled with a docking station and the existingHDMIsupport. A demo was

shown of a Microsoft Xbox controller synced with a tablet playing a game and the feedback appeared

quite fluid with minimal lag.

AndroidOpen Accessory

USB accessory mode is the other side of the new USB support, whereupon connected USB hardware

acts as the host. In that mode, the Android device will look for a corresponding application and launch it

to allow control of the accessory. For example things like robotics, musical equipment, docks, kiosks,

and other accessories are possible. Android 2.3.4 also includes support for the Open Accessory Library,

though it's an optional feature for particular device manufacturers to either enable or exclude support

for. The Open Accessory Library is an open platform for 3rd party hardware add-ons with no NDAs

andnofees to get started.

To demonstrate the openness of the Open Accessory Library, Google showed off an Arduino-based

development kit that was demonstrated running an accelerometer-controlled labyrinth game a physical

wooden labyrinth weighing over 5000lbs being controlled by an Android device. As the tablet was tilted
http://www.notebooklaptopreviews.net/2011/04/best-review-asus-eee-pad-transformer.htmlhttp://www.notebooklaptopreviews.net/2011/04/best-review-asus-eee-pad-transformer.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-details-on-intel%E2%80%99s-next-generation-cedar-trail-atom-platform.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-details-on-intel%E2%80%99s-next-generation-cedar-trail-atom-platform.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-intel-micron-announce-first-20nm-mlc-nand-flash-for-use-in-ssds.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-intel-micron-announce-first-20nm-mlc-nand-flash-for-use-in-ssds.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-the-motorola-xoom-giveaway-round-2.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-the-motorola-xoom-giveaway-round-2.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-the-macalope-weekly-terrible-mistakes.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-the-macalope-weekly-terrible-mistakes.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-the-motorola-xoom-giveaway-round-3.htmlhttp://www.notebooklaptopreviews.net/2011/04/best-review-acer-iconia-tab-a500.htmlhttp://www.notebooklaptopreviews.net/2011/04/best-review-acer-iconia-tab-a500.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-hauppauge-colossus-hd-pvr-with-hdmi-support.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-hauppauge-colossus-hd-pvr-with-hdmi-support.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-documents-reveal-new-lenovo-android-tablet-super-thin-notebook.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-documents-reveal-new-lenovo-android-tablet-super-thin-notebook.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-hauppauge-colossus-hd-pvr-with-hdmi-support.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-hauppauge-colossus-hd-pvr-with-hdmi-support.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-hauppauge-colossus-hd-pvr-with-hdmi-support.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-the-macalope-weekly-terrible-mistakes.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-the-macalope-weekly-terrible-mistakes.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-the-macalope-weekly-terrible-mistakes.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-details-on-intel%E2%80%99s-next-generation-cedar-trail-atom-platform.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-details-on-intel%E2%80%99s-next-generation-cedar-trail-atom-platform.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-the-motorola-xoom-giveaway-round-3.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-documents-reveal-new-lenovo-android-tablet-super-thin-notebook.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-documents-reveal-new-lenovo-android-tablet-super-thin-notebook.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-dell-brings-remote-desktop-capabilities-to-workstations.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-dell-brings-remote-desktop-capabilities-to-workstations.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-dell-brings-remote-desktop-capabilities-to-workstations.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-dell-brings-remote-desktop-capabilities-to-workstations.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-the-blackberry-playbook-review.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-the-blackberry-playbook-review.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-tim-cook-speaks-apples-coo-on-android-japan-ipad-2.htmlhttp://www.notebooklaptopreviews.net/2011/05/pc-world-new-intel-tablets-could-slow-ipad-enterprise-appeal.htmlhttp://www.notebooklaptopreviews.net/2011/05/pc-world-new-intel-tablets-could-slow-ipad-enterprise-appeal.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-tim-cook-speaks-apples-coo-on-android-japan-ipad-2.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-toshibas-tablet-arriving-in-june.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-toshibas-tablet-arriving-in-june.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-toshibas-tablet-arriving-in-june.htmlhttp://www.notebooklaptopreviews.net/2011/03/hardware-features-motorola-xoom-4g-verizon.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-toshibas-tablet-arriving-in-june.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-google-to-give-away-chrome-os-notebooks-for-10-20month-subscription.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-google-to-give-away-chrome-os-notebooks-for-10-20month-subscription.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-google-to-give-away-chrome-os-notebooks-for-10-20month-subscription.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-google-to-give-away-chrome-os-notebooks-for-10-20month-subscription.htmlhttp://www.notebooklaptopreviews.net/2011/03/hardware-features-motorola-xoom-4g-verizon.htmlhttp://www.notebooklaptopreviews.net/2011/04/best-review-asus-eee-pad-transformer.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-details-on-intel%E2%80%99s-next-generation-cedar-trail-atom-platform.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-intel-micron-announce-first-20nm-mlc-nand-flash-for-use-in-ssds.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-the-motorola-xoom-giveaway-round-2.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-the-macalope-weekly-terrible-mistakes.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-the-motorola-xoom-giveaway-round-3.htmlhttp://www.notebooklaptopreviews.net/2011/04/best-review-acer-iconia-tab-a500.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-hauppauge-colossus-hd-pvr-with-hdmi-support.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-documents-reveal-new-lenovo-android-tablet-super-thin-notebook.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-hauppauge-colossus-hd-pvr-with-hdmi-support.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-the-macalope-weekly-terrible-mistakes.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-details-on-intel%E2%80%99s-next-generation-cedar-trail-atom-platform.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-the-motorola-xoom-giveaway-round-3.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-documents-reveal-new-lenovo-android-tablet-super-thin-notebook.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-dell-brings-remote-desktop-capabilities-to-workstations.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-dell-brings-remote-desktop-capabilities-to-workstations.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-the-blackberry-playbook-review.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-tim-cook-speaks-apples-coo-on-android-japan-ipad-2.htmlhttp://www.notebooklaptopreviews.net/2011/05/pc-world-new-intel-tablets-could-slow-ipad-enterprise-appeal.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-tim-cook-speaks-apples-coo-on-android-japan-ipad-2.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-toshibas-tablet-arriving-in-june.htmlhttp://www.notebooklaptopreviews.net/2011/03/hardware-features-motorola-xoom-4g-verizon.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-toshibas-tablet-arriving-in-june.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-google-to-give-away-chrome-os-notebooks-for-10-20month-subscription.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-google-to-give-away-chrome-os-notebooks-for-10-20month-subscription.htmlhttp://www.notebooklaptopreviews.net/2011/03/hardware-features-motorola-xoom-4g-verizon.html


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in any direction, the labyrinth mimicked the movements. Arduino devices have long been used in home

automation and hardware development, and the ease of development forthis platform makes

it applicable to almost any imaginable device.

Android 3.1 alsogetssome UI updates to improve intuitiveness and overall refinement of the platform.

The launcher is smoother and more fluid, and navigation to and from home screens is easier tapping

home brings you to the last home screen used.

WiFi alsogetsits own update in Android 3.1, enabling a high-speed WiFi access mode to let

applications maintain high-performance WiFi sessions in the background even when the screen is

off. This allows for streaming music, video, and voice applications to continue with the screen off, such

as when the tablet is docked. HTTP proxy configuration per WiFI profile is also added, in addition to

Preferred Network Offload (PNO) support.

There are also a bunch of updates to the standard Google apps in Android 3.1. The browser gets a

number of tweaks and UI changes including an extended quick control UI.

http://www.notebooklaptopreviews.net/2011/05/latest-info-google-io-2011-keynote-updates-for-phone-tablet-tv-and-accessories.html

Android Platform Updates
http://www.notebooklaptopreviews.net/2011/04/pc-world-acer-expects-tablets-to-help-growth-this-year.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-lenovo-x1-leaked-sandy-bridge-gets-thin.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-lenovo-x1-leaked-sandy-bridge-gets-thin.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-lenovo-x1-leaked-sandy-bridge-gets-thin.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-lenovo-x1-leaked-sandy-bridge-gets-thin.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-lenovo-x1-leaked-sandy-bridge-gets-thin.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-lenovo-x1-leaked-sandy-bridge-gets-thin.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-acer-expects-tablets-to-help-growth-this-year.htmlhttp://www.notebooklaptopreviews.net/2011/05/latest-info-google-io-2011-keynote-updates-for-phone-tablet-tv-and-accessories.htmlhttp://www.notebooklaptopreviews.net/2011/05/latest-info-google-io-2011-keynote-updates-for-phone-tablet-tv-and-accessories.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-acer-expects-tablets-to-help-growth-this-year.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-lenovo-x1-leaked-sandy-bridge-gets-thin.htmlhttp://www.notebooklaptopreviews.net/2011/04/latest-info-lenovo-x1-leaked-sandy-bridge-gets-thin.htmlhttp://www.notebooklaptopreviews.net/2011/04/pc-world-acer-expects-tablets-to-help-growth-this-year.htmlhttp://www.notebooklaptopreviews.net/2011/05/latest-info-google-io-2011-keynote-updates-for-phone-tablet-tv-and-accessories.htmlhttp://www.notebooklaptopreviews.net/2011/05/latest-info-google-io-2011-keynote-updates-for-phone-tablet-tv-and-accessories.html


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First up is the update to Honecomb from 3.0 to 3.1. The update, which is being pushed out today to

Motorola Xooms on Verizon, includes a number of changes and optimizations, including an improved

task switcher, resizable widgets, UI improvements, and USB host and accessory support.

USB host mode support is a huge step forwards for making Android a versatile platform, as it enables

Android devices to connect to peripherals like mice, keyboards, mass storage devices, digital cameras,

audio devices, hubs, and more. USB host mode also enables gamepad and joystick support, includingPS3 and Xbox 360 wired controllers, USB Logitech gamepads, fight sticks, and car controllers. Almost

anything that would otherwise present itself as a USB accessory when connected to a PC will work with

Android tablets. Going forwards, it's clear that Android 3.1 could quickly become a gaming platform on

its own when coupled with a docking station and the existing HDMI support. A demo was shown of a

Microsoft Xbox controller synced with a tablet playing a game and the feedback appeared quite fluid

with minimal lag.

Android Open Accessory

USB accessory mode is the other side of the new USB support, whereupon connected USB hardware

acts as the host. In that mode, the Android device will look for a corresponding application and launch itto allow control of the accessory. For example things like robotics, musical equipment, docks, kiosks,

and other accessories are possible. Android 2.3.4 also includes support for the Open Accessory Library,

though it's an optional feature for particular device manufacturers to either enable or exclude support

for. The Open Accessory Library is an open platform for 3rd party hardware add-ons with no NDAs and

no fees to get started.

To demonstrate the openness of the Open Accessory Library, Google showed off an Arduino-based

development kit that was demonstrated running an accelerometer-controlled labyrinth game - a physical

wooden labyrinth weighing over 5000lbs being controlled by an Android device. As the tablet was tilted

in any direction, the labyrinth mimicked the movements. Arduino devices have long been used in home

automation and hardware development, and the ease of development for this platform makes it

applicable to almost any imaginable device.


15/20

Android 3.1 also gets some UI updates to improve intuitiveness and overall refinement of the platform.

The launcher is smoother and more fluid, and navigation to and from home screens is easier - tapping

home brings you to the last home screen used.

WiFi also gets its own update in Android 3.1, enabling a high-speed WiFi access mode to let

applications maintain high-performance WiFi sessions in the background even when the screen is off.

This allows for streaming music, video, and voice applications to continue with the screen off, such as

when the tablet is docked. HTTP proxy configuration per WiFI profile is also added, in addition to

Preferred Network Offload (PNO) support.

There are also a bunch of updates to the standard Google apps in Android 3.1. The browser gets a

number of tweaks and UI changes including an extended quick control UI.

http://www.anandtech.com/show/4327/google-io-2011-keynote-updates-for-phone-tablet-tv-and-accessories

Audio output was highlighted with whats currently known as Project Tungsten. Currently demonstratedas an edge lit black cube that connects through Android@Home to the cloud and integrates with thenew Music service to allow music streaming through connected speakers. Multiple Tungsten devicescan be manipulated individually giving Sonos-like levels of control.

MAY 102011
http://www.anandtech.com/show/4327/google-io-2011-keynote-updates-for-phone-tablet-tv-and-accessorieshttp://www.anandtech.com/show/4327/google-io-2011-keynote-updates-for-phone-tablet-tv-and-accessorieshttp://images.anandtech.com/doci/4326/home_full.pnghttp://www.anandtech.com/show/4327/google-io-2011-keynote-updates-for-phone-tablet-tv-and-accessorieshttp://www.anandtech.com/show/4327/google-io-2011-keynote-updates-for-phone-tablet-tv-and-accessories


16/20

Android Adds USB Host +Audio, Open Hardware

ADK with Arduino; GoodNews for Mobile Music

BY PETER KIRN

Android just got a whole lot more interesting for hardware development. We

can already run music apps and tools like Processing and (via libpd) Pure Data

patches on Android. Now, you should soon be able to plug in joysticks, custom

hardware, sensors, and other devices and make Android a go-anywhere live

music and visual platform. Updated: USB audio class is in fact

supported; awaiting other details.

The new hardware APIs allow anyone to develop hardware accessories for

Android, from individual DIYers all the way to brands. You dont have to sign

an NDA, and you dont need a special hardware license the aspects about

which Ive complained in the past with regards to Apple policies. Anyone can

do it.

Heres some of the documentation:

ADK Android Hardware Development Kit, based on Arduino (MEGA)
http://createdigitalmusic.com/2011/05/android-adds-usb-host-mode-open-hardware-development-with-arduino/http://createdigitalmusic.com/2011/05/android-adds-usb-host-mode-open-hardware-development-with-arduino/http://createdigitalmusic.com/2011/05/android-adds-usb-host-mode-open-hardware-development-with-arduino/http://createdigitalmusic.com/2011/05/android-adds-usb-host-mode-open-hardware-development-with-arduino/http://developer.android.com/guide/topics/usb/adk.htmlhttp://createdigitalmusic.com/2011/05/android-adds-usb-host-mode-open-hardware-development-with-arduino/http://createdigitalmusic.com/2011/05/android-adds-usb-host-mode-open-hardware-development-with-arduino/http://createdigitalmusic.com/2011/05/android-adds-usb-host-mode-open-hardware-development-with-arduino/http://developer.android.com/guide/topics/usb/adk.html


17/20

Android USB Accessory

USB Host Mode

In the keynote, Google even showed an Arduino MEGA-based board for doing

I/O. This should theoretically be open source hardware, though we dont yet

have specifications or code. Based on the way it was described, I would

imagine other Arduino boards would work, too, at least with modification.

Its also unclear what the relationship of the new Arduino-based stuff is to

the existing IOIO project, also based on Arduino and Android and with more or

less the same capabilities. Its very possible that what Google has done is add

official support. Official SDK support seems like a good thing; Im just unsure

what it means if youve already got an IOIO or how the two things relate. (It

should be a step forward in at least some ways. If you read the specs on IOIO

at Sparkfun, youll note that because of missing OS support IOIO has to

implement host mode itself. And handset support is limited. But IOIO is a

much better name.)

I wanted to get out there with the news, so Ill let you look through the

documentation if youre interested. Since Google IO isnt covered by an NDA

(cough, Apple), Im hoping well find out more details.

One very nice detail, aside from the Arduino support: the documentation

specifically calls out USB bus power.

This leaves some significant questions unanswered, however. For one thing,

despite Apples restrictions for hardware connected to the Dock Connector,

Apple has a very liberal policy and some brilliant hardware work when it

comes to USB connections made via the Camera Connection Kit. Power is

often an issue, but Apples iOS on iPad supports a wide range of USB device

classes, including USB audio and USB MIDI devices. Theres still no word on

whether thats supported on Apple which would be a major detail for music

use. (MIDI doesnt have to be a dealbreaker; you could certainly perform the

same functions via the existing classes, or even create your own Android-to-

MIDI adapter. .) USB audio is confirmed, as Google themselves cite it as an

example. Waiting on other specifics.

http://createdigitalmusic.com/2011/05/android-adds-usb-host-mode-open-hardware-

development-with-arduino/
http://developer.android.com/guide/topics/usb/accessory.htmlhttp://developer.android.com/guide/topics/usb/host.htmlhttp://ytai-mer.blogspot.com/2011/04/meet-ioio-io-for-android.htmlhttp://www.sparkfun.com/products/10585http://www.sparkfun.com/products/10585http://createdigitalmusic.com/2011/05/android-adds-usb-host-mode-open-hardware-development-with-arduino/http://createdigitalmusic.com/2011/05/android-adds-usb-host-mode-open-hardware-development-with-arduino/http://developer.android.com/guide/topics/usb/accessory.htmlhttp://developer.android.com/guide/topics/usb/host.htmlhttp://ytai-mer.blogspot.com/2011/04/meet-ioio-io-for-android.htmlhttp://www.sparkfun.com/products/10585http://www.sparkfun.com/products/10585http://createdigitalmusic.com/2011/05/android-adds-usb-host-mode-open-hardware-development-with-arduino/http://createdigitalmusic.com/2011/05/android-adds-usb-host-mode-open-hardware-development-with-arduino/


18/20

Separated at birth? The IOIO project. Photo courtesy sparkfun.com, who still sell this board and

incidentally, it remains useful for prototyping!

That said, let me review: weve now gotten things Id never really have

imagined given the early development of mobile apps. We have Arduino-

based and basic USB hardware on Android (possibly more), and USB MIDI andaudio devices on iOS.

And furthermore, I think people will do really, really cool things with this stuff.

The refrain from many advocates of mobile and next-generation platforms has

been that users dont need or want the kinds of capabilities that we get from

conventional computer experiences, and that us pundit nerds should stop

making comparisons to computers and let average users just check their

Facebook accounts. Yet Im pleased that engineers at places like Apple and

Google have added just those features, because I think a wide variety of

people not just nerds like me, indeed can do great, expressive things with

them, and that thats been a lesson of computing over the past decades.
http://sparkfun.com/http://sparkfun.com/


19/20

USB class for audio devices

http://developer.android.com/reference/android/hardware/usb/UsbDevice.html

USB host

http://developer.android.com/guide/topics/usb/host.html

http://www.synthtopia.com/content/2011/05/13/will-google-arduino-open-hardware-kill-the-ios-music-juggernaut/

Dear Bill,

iPad serving as a USB host for USB Audio devicesis an interesting & unexpected developmentindeed. I'm hoping to get a clearer picture ofthe current situation as well as Apple'sintentions for future of digital audio onportable devices. So far we've been working withLingo 10, but this might prove a useful addition.

I've got a number of questions and wouldappreciate your help in answering them:

First of all, our USB Audio products areexclusively running in Asynchronous mode, usingsync pipe for data rate feedback as per UAC 1.0specs. Does the iPad's current implementationsupport Asynchronous sinks? If not, are there anyplans to add the support?

You have mentioned that the presentimplementation only supports 16bit format. Willit enumerate a device with multiple interfacealternate settings, one of them being 16bit andthe other 24bit?

As for supported samplerates, is there a list ofrequired/mandatory samplerates like with Lingo10? (32/44.1/48k) Will it enumerate a device
http://developer.android.com/reference/android/hardware/usb/UsbDevice.htmlhttp://developer.android.com/guide/topics/usb/host.htmlhttp://www.synthtopia.com/content/2011/05/13/will-google-arduino-open-hardware-kill-the-ios-music-juggernaut/http://www.synthtopia.com/content/2011/05/13/will-google-arduino-open-hardware-kill-the-ios-music-juggernaut/http://developer.android.com/reference/android/hardware/usb/UsbDevice.htmlhttp://developer.android.com/guide/topics/usb/host.htmlhttp://www.synthtopia.com/content/2011/05/13/will-google-arduino-open-hardware-kill-the-ios-music-juggernaut/http://www.synthtopia.com/content/2011/05/13/will-google-arduino-open-hardware-kill-the-ios-music-juggernaut/


20/20

supporting 88.2k and 96k in addition to the basic32/44.1/48k?

When using Lingo 10, the iDevice sets the

samplerate according to the track currentlyplayed. This is unlike Mac OS X which alwaysoutputs at the samplerate set in Audio MIDISetup. How about iPad then - is it choosingsamplerate on-the-fly during playback or is itmore like a desktop OS X?

Is there an inherent difficulty in supportingformats upto 24/96 or is it just that nobody setthe goal so high as of yet? What about the audio

player in iPad - would it have any problemplaying back 24/96 Apple Lossless tracks?

Can I use HID media controls for play/pause,prev/next etc. alongside the Audio functionalityas part of my device to control the iPad?

Is this feature going to make it onto iPodtouch / iPhone along with OS 4 release or will it

be strictly iPad-specific?

Thanks!

Best Regards,Dominik_______________________________________________Do not post admin requests to the list. They willbe ignored.

Coreaudio-apiDate: Sat, 17 Apr 2010 00:16:34 +0800Dominik Peklo peachtree audio, audiolab

android 3.1 usb host

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