TAS2557: Using TAS2557 at 32kHz

HI Ben,

Welcome to e2e.

We don't usually support 32kHz as this is not a conventional audio sampling rate. Let me double check if we can setup internal clock settings for 32kHz on TAS2557.

One question:

• Is there a reason you're selecting TAS2557 instead of TAS2563?
  • TAS2563 is the latest smart amp release, it has a new and improved version of the speaker protection algorithm, and it actually supports 32kHz as you can see below from PPC3 End System Integration

Best regards,
-Ivan Salazar
Applications Engineer - Low Power Audio & Actuators

I'm not sure about the rationale behind picking the 2557, but I have arrived in the project at a time when it's far too late to do much about it!

Am currently exporting by multiplying frequencies *1.5, and reducing time constants /1.5, and testing on the EVM with audio played at 1.5x speed to check the limits still seem OK. I think this gives us a workaround but it'd be far more convenient to do this properly.

Ben,

Understood, I'm checking if we have any beta release that enables 32kHz sample rate. Will keep you update on the results.

Best regards,
-Ivan Salazar
Applications Engineer - Low Power Audio & Actuators

Thank you Ivan -- any update on this? With the current work-around, we have to hack the binary file's sampling frequency register which then causes a CRC issue, so it isn't a great solution.

Hi Ivan,

I am working on the same project and we are eagerly looking forward to your update on this.

Regards,

Chaithrika

Hi Ivan,

Would it help if we send the PPC3 project files so you can take a look at them and help us in getting the CRC issue resolved?

An alternative is that we could provide TI with either a .ppc3 or a .bin file, and TI hacks it for us to have the correct sample rate / CRC.

Hi, Ben, 

Ivan is out of the office this week. He will be able to provide additional support until Monday. Let me contact a member of my team in order to verify if he can continue the support. In the meantime, could you provide the .ppc3 and .bin files, please?

Than you.

Best regards,
Luis Fernando Rodríguez S.

Thank you Luis.

There are three files in this .zip that may be useful to you: I have provided an explanation of these in the readme.

Thanks for your help!

voicing_files_bensupper.zip

Hi, Ben,

I apologize for the delay. Our team is working to have an answer to this issue. We expect to have an answer today before the end of the day.

Best regards,
Luis Fernando Rodríguez S.

Hello again Luis.

As an indicator of the pressure we're under, we now have a Python script that converts the 48kHz .bin file to a 32kHz one and recomputes the CRCs and checksums, and addresses (as best it can) the undocumented parts of the DSP core.

But obviously this is was a pain to write, and will be hard to maintain, and we'd much rather have your solution. How're you doing?

Hi, Ben,

I've been in contact with our software team. We are hardly working in order to see if we can include the 32KHz option in a beta version of PPC3. Our team is taking this as priority to have you an answer soon, but since it requires some changes in the software, it may take some additional time. I will be constantly updating this e2e thread in case we receive feedback from our team.

Best regards,
Luis Fernando Rodríguez S.

Thanks Luis: we appreciate the effort. We'll keep updating this thread too.

Hi Ben,

We have the beta version supporting 32kHz sample rate using Tuning Mode. Just want to confirm you're using Tuning Mode, is it correct?

Please provide an email in a reply or through a private e2e message so I can share the download link with you. Or you can reach out to me directly at: ivan.salazar@ti.com

Best regards,
-Ivan Salazar
Applications Engineer - Low Power Audio & Actuators