ADAU-1777 and ADAU-1787
Hi All
Sorry if this has been posted before.
We are currently trying to evaluate the ADAU-1777 and as such have bought the EVAL-ADAU1777Z Evaluation Board.
What we are aiming to do is sample the coming signal do some processing and then capture the result of the processing in the digital domain. As such, we would like to know if there is any way to access the sampled values, either before or after process, via the digital interface (SPI or I2C). Is this possible?
I have also seen that it may be possible to output the processed data as serial stream from one of the multipurpose pins. How can this be achieved on the Evaluation Board. I have tried modifying various hardware parameters but cannot seem to achieve anything. I am probing the output pins with an oscilloscope - I am expecting to see a square pulse train representing the sampled or processed signal - is my understanding correct? Anyone know what I may be doing wrong.
Another question is - can this DSP be programmed directly without SigmaStudio? Is so how. I am correct in thinking that the DSP is quite limited in what it can do?
We are planning to actually implement the final system using the ADAU1787, but I we could not get hold of the Evaluation Board. Would the above be possible on this chip - i.e. outputting the processing results via the control interface? Or would we again have to use the serial streaming method to access the sampled and processed data? Can this chip be programmed directly without SigmaStudio.
Another question is that I have Version 4.2 of SigmaStudio but cannot seem to see the ADAU1787 listed as a Processor that can be selected. I understand that this may be in the Beta version. Anyone have any idea when the Beta version will be formally released?
Thank you again and apologies for the number of questions within one post.
Anand
Hello Anand,
It sounds like you're on the right track. The most effective way to probe the data at a particular point in the ADAU1777 would be to take a digital output at the point you want to probe. To easily route the data to a digital output, do the following:
In the "Chip Control" tab in the ADAU1777 Register Control in SigmaStudio, ensure that ASRC Interpolator 0-1 are enabled, and ASRC 0-4 are enabled.
In the "Signal Routing" tab, enable the output ASRC.
In the "Output/Serial Port" tab, configure your serial port as desired. For probe purposes, it's probably easiest to set the LRCLK/BCLK mode to Master, unless you're already providing external clocks.
In your SigmaStudio schematic, use output 0 for the output you wish to probe digitally.
With these settings, you will be able to view the serial output by monitoring the BCLK, LRCLK, and ADC_SDATA0 pins on the EVAL-ADAU1777Z. Bear in mind that your output may not be completely bit-accurate, because it will pass through an ASRC.
It is possible to program the ADAU1777 via any I2C or SPI interface, but development of signal flows must take place in SigmaStudio. It is a limited DSP -- it is designed with a reduced instruction set optimized for noise cancellation, in order to achieve lowest-possible latency.
Now, regarding the ADAU1787: due to the more flexible routing options available on the ADAU1787, it would be a more straightforward process to pass data directly from a core to a serial output. Again, the ADAU1787 can be programmed via any I2C or SPI interface, but development of the signal flow will require SigmaStudio. The latest beta version of SigmaStudio (4.3.3 beta) features the ADAU1787.
Hope this helps!
Best regards,
Tyler Krome
Dear Tyler
Thank you very much for your reply.
I think I was (am) doing two things wrong - I didn't set the LRCLK/BCLK clocking mode (on the Output/Serial Tab) to master and did not enable the ASRC Interpolator. I am currently on something else today but I will try this later.
Just to confirm - there is no way to get the sampled data out via the SPI/I2C interface on either the ADAU1777 or ADAU1787? Does SigmaStudio allow the creation of custom processing routines that can be executed by the DSP (here I am referring to the ADAU1787) or are we limited to the blocks provided by SigmaStudio?
Also is there any way for the sampled and processed data to be stored to an external memory eg EEPROM? If not, are there any chips in the same range (i.e. with low power consumption) that has this facility?
You note that the serial stream from the device may not be bit accurate due to the ASRC, do you know how inaccurate the data may be?
Finally, is the beta stable enough to do production development?
Thank you once again for you help.
Anand
Hi Anand,
The standard digital data format for the ADAU1777 is I2S/TDM. That's the best way to sample data at any point, since it's a representation of the audio data that's being processed. It would theoretically be possible to get an idea of the data over I2C/SPI by sending the data from some point in your schematic to one of the DBREG outputs, but doing so would convert the data frame to dB, which would probably be more of a headache to decode than just using I2S/TDM.
SigmaStudio does not contain the ability to custom-code blocks, although the SigmaDSP core of the ADAU1787 has a ton of flexibility in terms of what you can create using the existing blocks. If you do require truly custom code outside the scope of what's available, our software team may be able to help support your efforts, or we can refer you to a third-party developer who can help. If you're able to share some details about your application (you may e-mail me privately at tyler.krome@analog.com if it's not possible to share publicly), I can give you more specific feedback on how to best accomplish it.
Sampling and processing data, then storing it to an EEPROM may be possible with some of our more powerful SigmaDSP chips, but the exact mechanism of doing it could require a microcontroller in the system. Again, I would need to know more exact details to be able to give an exact answer.
The ASRC in the ADAU1777 has a dynamic range of 100dB, so data would typically be accurate to 16 bits.
We believe the beta to be fairly stable, but it does contain new features that haven't been "out in the wild" for very long. However, for prototype development, the beta version of SigmaStudio should work well to get you started -- when the full release comes, any files you've developed in the beta will be compatible with the full release.
Hope this helps!
Best regards,
Tyler
Please log in to reply.