USB DAC Project for HPA

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JPS64
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USB DAC Project for HPA

Post by JPS64 »

Hello,

I´m just designing a Class A Headphone Amplifier (Amplifier ready) and I need now an USB Audio DAC (PCM and DSD).

The xCORE-AUDIO Hi-Res DAC/HPA Platform (with ESS DAC) is the ideal candidate but the Silicon XHRA-2HPA-TQ64 is obsolete.

Can I replace this one with another one without a lot of work. Of course, I´ll design a new PCB layout.

Thank you in advance,
JP


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andrewxcav
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Post by andrewxcav »

This should be doable on just about any xcore 200 device. The easiest thing to do is pick one that has a reference design:

https://www.xmos.com/support/software/uac2

That dev board is really great for prototyping, but the actual silicon on it should be a widely available xcore 200 part.
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infiniteimprobability
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Post by infiniteimprobability »

Can I replace this one with another one without a lot of work. Of course, I´ll design a new PCB layout.
Yes - in fact it should be possible to be pin compatible so no need for a new PCB.
This should be doable on just about any xcore 200 device
andrewxcav is right, although pick the XU208-128-QF48-C10 and it should be pin compatible.

We are talking internally at the moment about making an example project, based on https://www.xmos.com/support/software/uac2, that will get you most of the way there..
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JPS64
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Post by JPS64 »

Thank you for the answers.

I´m starting schematics and publishing for control.

JP
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JPS64
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Post by JPS64 »

Hello,

as promised, here the schematics.

Could someone do the mapping, table is in the schematics.

Should I use xSYS header, JTAG only or full xSYS header?

Regards,
JP
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infiniteimprobability
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Post by infiniteimprobability »

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JPS64
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Post by JPS64 »

Thank you!

I´m following your recommendation: anyway, I need an additional I2C interface to µC to be able to configure filters and to read mode and sample frequencies.

Here the first layout: I´m using MILL-MAX SLC Header during development.

JP
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mon2
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Post by mon2 »

Correction - IF this design will be bus powered..(appears you are self powered using an external power source?)

Please add the inrush current protection onto the Vbus rail else you may face field failures. The latest datasheets for the processor offer one version of protection. There are other methods including the use of the USB load switch devices from Diodes Inc. (ie. AP2331) or similar.

Add a pull-up onto pin 4 (N9) of your reset supervisor. This pull-up may not need to be stuffed but place into your design as a CYA (cover your ....).

Wurth (L5) is a good company but expensive. Consider a review of the Taiyo Yuden inductors. Very cost effective and excellent quality.

https://www.xcore.com/viewtopic.php?t=5808

Perhaps consider to add some debug interface signals (XSYS interface) ?
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JPS64
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Post by JPS64 »

Hi mon2,

thanks you for the comments: schematics attached.

Yes, correct, board is self powered and suggested XMOS inrush current protection added.

This board is mounted on testboard supplying Mill-Max springloads and external Glue (USB connector, RESET hold switch and so) for test and manufacturing (debugging using full xSYS-Header, flashing SPI FLASH): pull-up on RESET external.

When board functional so directly soldered on motherboard: powered with +5VDC, using I2S/DSD, I2C, logic to DAC; interfacing I2C to micro for GPIO (filter selection).

JP
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