Developing a USB to I2S application but need some help.

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Developing a USB to I2S application but need some help.

Postby Boscoe » Sun Feb 14, 2016 8:20 pm

Hi there, I'm having a few problems and it would be good if someone could help me!

I'm interested in developing an audio bridge using Xmos parts and have a few questions.

First; I have been browsing the Xmos website and downloading the documentation and software examples but haven't come across an example for straight USB to I2S which does surprise me as I thought this would be the most popular use for the XMOS-AUDIO part. The Xmos audio micro controller seems to be 'the solution for audio' but the xcore multichannel uses a different 'generic' part so what's the point in the XHRA-2HPA-TQ64 part?

Second; I have downloaded xTimeComposer but it doesn't run on my Windows PC (all other Eclipse version do). I click on the shortcut but absolutely nothing happens. I have it running fine on my MacBook Air.

Third; I have been having a look through the examples on xTimeComposer but I can't seem to start a project for the XHRA-2HPA-TQ64 xcore audio part. Is this because I don't have the target installed or else?

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Postby henk » Mon Feb 15, 2016 9:42 am


XMOS processors are generic processors - the same silicon can be programmed to bridge USB to I2S, or to drive a robotic vacuum cleaner. You need to write or download software that make it do what you want it to do; and different software (and different IO devices on the outside) make the generic processor into a specific solution.

The XHRA part is pre-programmed to just do USB-audio; as such it is much simpler to use if you just want to do USB-audio. Needless to say, this pre-programmed part cannot be used to control a robot.

There are plenty of people who buy the generic part, even though they just want to implement USB-audio. It enables them to customise the software to do USB-audio the want they want to. It might just be a small bit of DSP, or a more complex intervention.

I am not sure what you have in mind with just USB to I2S; but I guess that the XHRA part and design around it does exactly what you want it to do.

Since the XHRA part is pre-programmed; you cannot program it from xTIMEcomposer; or anywhere else for that matter.

I am not sure why xTIMEcomposer won't run on Windows - maybe something with a version of Java? I hope somebody else can help.
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Postby Boscoe » Mon Feb 15, 2016 9:54 am

Thanks for the reply.

I have done a little more digging and found this out too. The problem I found is that there isn't anywhere that says this about the XRHA. Not on it's webpage or the brief sheet nor the datasheet I think.

But what is on the webpage for the part has suggestions for documentation like the USB Programming Guide and software like xTime.

Generally I find the XMOS documentation vague. Especially the website when it comes to informing the customer exactly what they're products are and how they differ.

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