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Hot!Asynchronous OUT endpoint with rate feedback?

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chinzei
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Re: RE: Asynchronous OUT endpoint with rate feedback? 2010/09/30 08:55:37 (permalink)
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Now I'm trying to make rate feedback work in Mac OSX (Snow Leopard),

Apple opens the source code of MacOSX kernel and drivers.
This source code obviously shows the way how the OS behaves.

Mac OS X 10.6.4 Source - AppleUSBAudio-273.4.1
http://www.opensource.app...ppleUSBAudioStream.cpp
 
AppleUSBAudioStream.cpp

IOReturn AppleUSBAudioStream::checkForFeedbackEndpoint (AUAConfigurationDictionary * configDictionary)
{
    ...
    if (kAsynchSyncType == syncType)
    {
        ...
        if (assocEndpoint != 0)
        {
            ...
            if (kUSBDeviceSpeedHigh == mUSBAudioDevice->getDeviceSpeed())
            {
                // Request 4 bytes for the 16.16 value if the endpoint allows it
                mFeedbackPacketSize = (maxPacketSize < kFixedPoint16_16ByteSize) ? maxPacketSize : kFixedPoint16_16ByteSize;
            }
            else
            {
                mFeedbackPacketSize = kFixedPoint10_14ByteSize;
            }


Tsuneo

post edited by chinzei - 2010/09/30 13:38:57
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alexlee188
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Re: RE: Asynchronous OUT endpoint with rate feedback? 2010/09/30 18:34:42 (permalink)
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Hi Tseuno,


Many thanks.  I'll try with 16.16 and see whether it works Smile


Alex


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alexlee188
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Re: RE: Asynchronous OUT endpoint with rate feedback? 2010/09/30 20:12:34 (permalink)
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Hi Tsuneo,


Many thank.  I can confirm 16.16 rate feedback works with OSX.


btw, you might be interested to know that our project is an open source hardware and open source firmware sound card.  (Google for sdr-widget.)


We now have firmware that works in UAC1, 48khz 24 bit stereo capture and playback, as well as UAC2, 48/96/192khz 24 bit stereo capture.  We are starting to write the firmware for UAC2 48/96/192khz playback.


UAC2 capture works with Linux (kernel 2.6.35 or later) and OSX Snow Leopard.  ASYNC IN with implicit feedback.
UAC1 capture works with all OSes, ASYNC IN with implicit feedback.  UAC1 playback ASYNC OUT with rate feedback now works in OSX and Linux.  We are going to test with Vista and Win7 soon.


We also have a version of firmware, UAC1 with SYNC playback (no feedback) working in all OSes, including WinXP.


The emphasis of our hardware is capture, as it is designed to be used for amateur radio receiving.  The capture performance, in terms of noise floor and blocking dynamic range, is better than any of the commercial sound cards that we have tested  (We have not tested against the EMU1212M and the Pro Audio rack mounts yet.)


Alex




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bboyandru
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RE: Asynchronous OUT endpoint with rate feedback? 2011/08/21 02:19:26 (permalink)
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  Hi, I have read almost all discussions regarding this subject on microchip forums. Can you please help me with some information about feedback endpoint? First, I don't understand how the host is requesting feedback info. Is there any specific request for this? In my understanding SYNCH_FRAME is used to report the number of frames(though I have never seen this request). How can I send the feedback info to the host (which, in my understanding can be a number in 3 bytes, in 10.14 format). regards, Andrei
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stefanopod
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Re:Asynchronous OUT endpoint with rate feedback? 2011/08/21 14:15:06 (permalink)
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For the theory about this issue you should study USB Audio standard papers.
I  posted the code of a complete example, working under windows 7, in 2010.
The way  host asks informations is  an IN transaction from the feedback endpoint.

provando e riprovando
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MisterHemi
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Re: RE: Asynchronous OUT endpoint with rate feedback? 2019/09/28 23:48:42 (permalink)
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I know this is an old post but some of the information would be useful to me, however some of the links are dead.
 
I'm looking at USB Audio 2.0 and 3.0 and trying to understand how the asynchronous feedback endpoint works and how to implement it.
 
I have a lot of things working for USB Audio 2.0 but not the feedback endpoint.
 
Any good references?????

My configuration:
MacBook Pro (Retina, 15-inch, Mid 2015) with MacOS High Sierra (10.14.5) and MPLAB X IDE v5.20
 
Curiosity PIC32MZ EF, PIC24F Curiosity, XPRESS EVAL BOARD (PIC16F18855), SAMA5D3 Xplained and various custom boards.
#26
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