Playing with the ADAU1761 audio codec

I've been attempting to use the ADAU1761 chip, just using I2S audio stream generated by the PL section.

After a bit of playing I've at least got a 440Hz tone out of one channel of the headphones, so I'm slowly getting there.

I'm working towards at least a I2S loopback for playing with digital filters (e.g. Line In -> I2S -> PL -> I2S -> Line Out + Headphones).

Anyhow, in the spirit of release early, release often you can find the source at http://hamsterworks.co.nz/mediawiki/index.php/Zedboard_Audio

0 Former Member over 11 years ago

Hi again, just realised why audio is in one channel - the write to register 0x401F should be going to 0x401E.

Will test and update the archive later today.
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0 Former Member over 11 years ago

I've found some time to play, and now have an updated version that implements the full LineIn => ADC => I2S => Zynq's PL => I2S => DAC => Headphone.

So I can now start to play around with DSP filters for audio within the PL - I can just plug my iPod into Line In and listen to the result on the Headphone socket or using the Line Out
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0 Former Member over 11 years ago

Project now complete. LineIn / filters in Zynq's fabric / Headphone Out.

Overall gain should be about 0db, but haven't metered it.

Filter can be selected by SW0 and SW1, and are either
- Straight through
- 8 point moving average (6kHz low pass)
- 16 point moving average (3kHz low pass)
- 32 point moving average (1.5kHz low pass)

Warning - The design cuts straight between filters, so you will hear loud switching noise at full volume. So take you ear-buds out when playing with the switches

http://hamsterworks.co.nz/mediawiki/index.php/Zedboard_Audio
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0 Former Member over 11 years ago

I've added the following enhancements:
- Full 24-bit per channel samples are used
- Codec mute is turned on when switching filters, reducing painful pops.
- All the messy hardware specific bits are wrapped into one component.
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0 Former Member over 11 years ago

Hello,
How would I set up your project to see it work? I've got a zedboard and am using Vivado. I would guess that I import the vhdl and c code, somewhere along the line I'd need to setup a lot of other variables?
Clearly I'm a beginner.
Thank you very much for any help!
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0 Former Member over 11 years ago

Hello hamster,
I read your very good tutorial. Although it helped me a lot to unterstand basics, I'd like a little help about how to set up the audio codec whith Vivado. So far, I think that I have to use both PS and PL to do the trick. PL (a .vhdl file) to tell how the I2S signal have to be processed and PS to configure the codec with a .c code file. I guess that there are a lot ow ways to do this but could this method be right ? As you can guess, I'm a little bit confused about the mechanism more than the details :-)

Thank you for your help
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0 Former Member over 11 years ago

Hmm - looking at the VHDL - (and I'm not vhdl/verilog guy) - the VHDL seems to be standalone, and does not have an interface the processor can access. Is that correct?

I'm looking for a memory access port, where I can control the I2C signal and write IIS audio data - I don't see that.

Thanks.
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0 Former Member over 11 years ago

Hello hamster,

I am beginner for zedbaord.

I am trying to execute your project "Zedboard dsp base project.zip". But I did not get any output on headphone.

There is file "i3c2program" which is configuration file for codec. But I do not know how to use this file. Will it automatically get configured once I do synthesis, generate programming file and program zedboard.

Thanks.
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0 Former Member over 11 years ago

Hi, Been away on holiday.

1) Yes - it is a PL only design - jsut to test the codec. If anybody wants to adapt it to interface with the PS, support VDMA, write a linux driver and so on then you will need to do a lot of work.

The I3C2 program is already included - it is used to generate a script for a I2C state machine/controller that does the actual work - see http://hamsterworks.co.nz/mediawiki/index.php/I3C2

So if you do connect up the I2C port to the PS, the script will give you a starting point for register settings required to configure the codec to send/receive I2S.

Mike
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0 Former Member over 11 years ago

Hi hamster,

Thank you for reply. I programmed zedboard but only humming is coming out and not what I speak in microphone. When I select different filters, I can notice the reduced noise. It means filter part is working. Can you suggest some solution?

Thanks again.
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