zybo audio streaming

[RATHNA]

is streaming of audio from mic in to hph out is possible in zybo z7-20 variant board?...if it is possible how to do it?....i verified the dma demo project in website,but I don't know how to stream the audio without delay?

[RATHNA]

can you please reply fast?

 

[artvvb]

Hi @RATHNA,

Sorry for the delay.

The DMA audio demo isn't designed around being able to stream audio through the board in real-time. On a cursory look through the I2S audio IP's VHDL sources, I think that it should be able to have both the input and output streams active at once. That said, I'm not sure, and the rest of this reply depends on that assumption. The first thing I'd try to do would be to modify the demo's software to start up both the output stream just after the input stream, as in something like this in demo.c:

case 's': // add a new case to the Demo.chBtn switch statement
	fnSetLineInput();
	fnSetHpOutput();
	fnAudioRecord(sAxiDma,NR_AUDIO_SAMPLES);
	Demo.fAudioRecord = 1;
	fnAudioPlay(sAxiDma,NR_AUDIO_SAMPLES);
	Demo.fAudioPlayback = 1;
	break;

There will be an unknown latency between the input and output (due to the time it takes the software to start the output, and data transfer latency between PL and DDR), and streaming will still be limited to a fixed number of samples before it has to be restarted.

For actual real-time streaming, hardware changes are necessary. Stripping out DMA functionality and looping the AXI stream output of the I2S core back to the AXI stream input would be a start. I would look at something like this:

I'm not sure if this will work - the FIFO size could be relevant to make sure data doesn't back up and cause errors, but there are also FIFOs in the I2S IP. Substantial software changes would also be necessary to make sure that the application doesn't try to interact with the DMA.

Hope this helps...

Arthur

 

[RATHNA]

i'm beginner in this...i tested only demo projects...can you help me to make the audio stream

[RATHNA]

how to access the case s