Is it posible to get inverted one channel data output in USB Topic is solved

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Dohny
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Is it posible to get inverted one channel data output in USB

Post by Dohny »

Hello, I builded a USB audio transport based on reference USB audio 2.0 design software and I need to invert ONE channel (only right) phase polarity (by inverting a data sample for right channel), is there any chance to do it by software? Thank you very much.



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infiniteimprobability
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Post by infiniteimprobability »

This is nice and straightforward. There are lots of places you can do this in the data path but you could do it close to the pin. That means:

/sc_usb_audio/module_usb_audio/audio.xc. Look in the deliver function for:

            for(int i = 0; i < NUM_USB_CHAN_OUT; i++)        
            {
                samplesOut = inuint(c_out);
            }
 
This is where I2S gets the sample from the decouple core over a channel. In stereo, NUM_USB_CHAN_OUT = 2 so you can pick your channel and do:
 
samplesOut[0] = - samplesOut[0]; 
 
for example..