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Old 17th March 2013, 10:45 AM   #81
mkc is offline mkc  Denmark
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Hi BÝrge,

Ok, I haven't looked much on the prices, but instead looked at which package they where available in. BGA is difficult to solder at the kitchen table.

However, I assume that the SAM3UC is the cheapest of the two. My interest in the STM32F4 series was also due to the ethernet MAC and the DSP capabilites of the Cortex M4.

I actually bought a AB-12 as I thought you already had changed the AVR32 to a SAM3UC.

But, you can get back to me if there is any interest.

Mogens
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Old 17th March 2013, 05:34 PM   #82
davada is offline davada  Canada
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Hi Morgens,

What would it take to add auto sync to either an I2S or an SPDIF input which can sense a change of sample rate from an ADC and set the firmware up according?
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Old 17th March 2013, 05:51 PM   #83
mkc is offline mkc  Denmark
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Hi David,

First I have to admit that I don't know if there is anything USB releated by the ADC changing sample rate autonomously.

But, apart from that I think it would be resonably easy if a SPDIF reciever was to be used. I have some WM8805 around here that might be ok for the job. Perhaps Demian has some suggestions to this.

As for I2S, I don't know if there is any possibilities for (mis)using one of the peripherals on the selected processor for some detecting scheme.

Mogens

Last edited by mkc; 17th March 2013 at 06:08 PM. Reason: clarification
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Old 17th March 2013, 06:44 PM   #84
RNMarsh is offline RNMarsh  United States
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Location: 2457 Cascade Trail; Cool, CA. 95614
FYI - Intermission - Cool Little device for retail of only $30! at FRY's Electronics store. You get an ADC. Takes your L and R analog and converts to digital for your new reciever or other digital products. A transistion piece. uses Cirrus CS8427, 5340 and a EM78P153 8-bit mucro proc. Not that it is what you are doing here but just to acknowlege that digital ship has really left the analog shores. Analog is officially - Legacy.

-THx RNMarsh
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Old 17th March 2013, 07:14 PM   #85
1audio is offline 1audio  United States
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I have already brought up the use of this chip http://www.asahi-kasei.co.jp/akm/en/...k4115_f01e.pdf with the audiowidget. I covers three tasks, SPDIF out, SPDIF in and clock generation. It has the ability to detect the incoming clock frequency and communicate it.

The easiest way to see how a system would work is to read through the UAC2 spec here http://www.usb.org/developers/devcla...o2.0_final.zip , its only 144 pages. I believe the driver would generate an interrupt to tell the system when a sample rate change is detected. I'm not sure how the applications would handle that. I suspect most will just crash and you will need to restart them. I can try that later today I think, using the PCI interfaces I have.
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Old 17th March 2013, 08:43 PM   #86
davada is offline davada  Canada
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Quote:
Originally Posted by 1audio View Post
I have already brought up the use of this chip http://www.asahi-kasei.co.jp/akm/en/...k4115_f01e.pdf with the audiowidget. I covers three tasks, SPDIF out, SPDIF in and clock generation. It has the ability to detect the incoming clock frequency and communicate it.

The easiest way to see how a system would work is to read through the UAC2 spec here http://www.usb.org/developers/devcla...o2.0_final.zip , its only 144 pages. I believe the driver would generate an interrupt to tell the system when a sample rate change is detected. I'm not sure how the applications would handle that. I suspect most will just crash and you will need to restart them. I can try that later today I think, using the PCI interfaces I have.
The AKM you linked to is not the one I was looking at before. This one certainly meets our requirements. Where would you put this?

With the EMU1212 if another app tries to change the sample rate an exception is thrown.
Windows calls a debugger usually drwatson and then closes the offending app. If emu had handled the exception I don't think this would happen. This is how it is with XP on my machine. Because I have VS 2010 installed a different debugger is called and I get a bit more information. ARTA doesn't crash if I change the sample rate in the EMU DSP app.

With the EMU0204 if I change the sample rate in the driver's control panel the sample rate changes in ARTA. I think it comes down to how it's handled by the driver.
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Old 17th March 2013, 08:51 PM   #87
davada is offline davada  Canada
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For anyone following along who is interested I came across this app note 'USB AUDIO CLASS TUTORIAL' which has a brief overview of usb isochronous transfer.

http://www.silabs.com/Support%20Docu...Docs/AN295.pdf
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Old 17th March 2013, 08:58 PM   #88
borges is offline borges  Norway
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Thanks David, good link!

You saved my commute tomorrow morning :-)

BÝrge
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Old 17th March 2013, 11:55 PM   #89
1audio is offline 1audio  United States
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I must point out that Win 7 handles audio very differently from XP. XP generally is better for measurement.

I just tried an experiment with the RME, the Juli ARTA and Praxis. I routed the digital output of the RME to the digital in of the Juli@ card. The Juli is set to external clock. The Juli now tracks the clock from the RME. From the control panel on the RME I can switch sample rates at will. I set both Praxis and ARTA to do an FFT and then, while measuring, I switched the sample rate from 192K to 96K. In both cases, except for a bad measurement it all ran right through. I am now setting up a CMEDIA 6631 demo board that has SPDIF in and I'll see what happens.
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Old 18th March 2013, 12:08 AM   #90
1audio is offline 1audio  United States
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I could not get the CMEDIA SPDIF input working. This will need to wait for later.

Has anyone had success with the EMU 0404 SPDIF input? It seems its only for external clock sync.
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