8M Plus - Asynchronous Sample Rate Converter (ASRC)

[djsftree]

Hi,

Section 14.5 descibes the ASRC in the 8M Plus.

This looks more advanced that previous ASRC in Freescale MCUs.

I am particularly interested in the FIR / IFIR pre-filters per context - see 14.5.2.7

Are there any plans to bring this advanced filtering functionality to the ALSA plugin?

https://github.com/nxp-imx/imx-alsa-plugins

If not, do you have any example code for the FIR / IFIR filtering contexts?

I'm seeing some traffic regraing the ASRC for the 8M N

https://github.com/Freescale/meta-freescale/pull/1389

It looks like it requires a firmware binary for coefficients.

https://github.com/Freescale/meta-freescale/commit/2cc7e931cdae51aeb2eeddb69b2c0a16784fa8d8

dts looks like it shows firmware binary too

https://www.kernel.org/doc/Documentation/devicetree/bindings/sound/fsl%2Ceasrc.yaml

[djsftree]

Thanks Sanket.  I look forward to using the ASRC soon!

[Sanket_Parekh · Accepted solution]

Hi @djsftree 

I hope you are doing well.

Are there any plans to bring this advanced filtering functionality to the ALSA plugin?

[Ans]: We can't share this information until the next BSP release.

Yes, ASRC requires firmware binary.

It is referenced in easrc node at imx8mp.dtsi as below.

firmware-name = "imx/easrc/easrc-imx8mn.bin";

firmware binaries can be placed at /lib/firmware/imx in rootfs

One can download firmware binaries using as below.

$ wget https://www.nxp.com/lgfiles/NMG/MAD/YOCTO/firmware-imx-8.18.bin

$ chmod +x firmware-imx-8.18.bin

$ ./firmware-imx-8.18.bin

easrc binary can be found at ~/firmware-imx-8.18/firmware/easrc

One can refer to /sound/soc/fsl/fsl_easrc.c

Thanks & Regards

Sanket Parekh

[praveen_yaramada]

Hello @Sanket_Parekh ,

I'm following up on a previous discussion where it was mentioned that we'd need to wait for the next BSP release to see advanced filtering support integrated into the ALSA plugin. Now that some time has passed, I was wondering if these plans have materialized? Is there a merge request or any reference available that details this integration?

Best regards

Praveen