Analog Signal Pass-Through on EV-SC598-SOM

Hi Nurmukhammad,

We believe the Audio_Talkthrough_I2S example provided in the BSP will meet your requirements.
Here’s the flow of the Audio_Talkthrough_I2S example. Here TWI is used to set up the ADC and DAC.

As you intend to supply analog input to the ADC and obtain output from the DAC, you may directly utilize this example.
This example demonstrates using buffers int_SP0ABuffer1, int_SP0ABuffer2, int_SP0ABuffer4 and int_SP0ABuffer5 as user defined buffers. The input data received from the ADC is written into int_SP0ABuffer4 and int_SP0ABuffer5 buffer via SPORT4B.

The data in int_SP0ABuffer4 is copied to int_SP0ABuffer1 and data in int_SP0ABuffer5 is copied to int_SP0ABuffer2. The copied data (int_SP0ABuffer1, int_SP0ABuffer2) is then sent to the DAC through SPORT4A.
In the ADSP-SC598 EV-SOMCRR-EZKIT, audio jack J12 is connected to ADC channels 1 and 2, while J17 is connected to DAC channels 1 and 2. Please refer the EV-SOMCRR-EZKIT schematic for more details in the below link.
https://www.analog.com/media/en/technical-documentation/eval-board-schematic/ev-somcrr-ezkit-schematic.pdf

In ADSP-SC598 EV-SOMCRR-EZKIT, ADC supports sampling rate range from 8kHz to 192kHz. We can set this sample rate ranges by setting 0 to 2 bit of the ADC SAI_CTRL0 register. For more information refer the Table 20. Bit Descriptions for SAI_CTRL0 in ADAU1979 datasheet. But, DAC only supports the sample rate range from 32kHz to 192kHz. We can't set the sample rate below the 32kHz in DAC register. For more information refer the Table 31. Bit Descriptions for DAC_CTRL0 in ADAU1962A datasheet. The example provided uses a default sample rate of 48 kHz.

Please refer the ADAU1979(ADC) and ADAU1962A(DAC) datasheets in the below link:
https://www.analog.com/media/en/technical-documentation/data-sheets/adau1979.pdf

https://www.analog.com/media/en/technical-documentation/data-sheets/ADAU1962A.pdf

For more information regarding SPORT, please refer the Hardware Reference Manual in the below link.
https://www.analog.com/media/en/dsp-documentation/processor-manuals/adsp-sc595-sc596-sc598-hrm.pdf

Could you please confirm if you’ve tested the example without any modifications? If yes, please provide audio input to the ADC and let us know if you can hear the correct output from the DAC.
Alternatively, if you have made any modifications to the example, please let us know the changes.

Regards,
Nandini.C

I have not modified anything in the example project. I tried to load and run the example project on the board and got following result in the console. However, nothing has changed related to the waveform generator and digital storage oscilloscope. The input is sin signal:

Hi Nurmukhammad,

Thanks for your inputs.

As stated earlier, could you please check by supplying audio input to the ADC and let us know if the DAC output through the headphones is accurate?

Regards,
Nandini C

Hi Nandini,

Thank you for your follow-up. I’ve tested the example project with an audio input signal directly into the ADC and connected the output to headphones via the DAC. Unfortunately, I am still not receiving any output signal from the DAC. I double-checked my connections, and the sine wave input is functioning as expected from the waveform generator.

Here are a few additional details from my setup:

• I’m using a 1 kHz sine wave input to the ADC channels 1 and 2 through J12.
• The DAC channels 1 and 2 are connected to Oscilloscope as an output at J17.
• No modifications have been made to the sample rate or the default settings in the example.

Could you advise if there’s any further diagnostic step I should take? Also, is there any way to confirm whether the ADC is successfully receiving the signal, or if there’s an issue between the ADC and DAC data transfer?

Thanks again for your support!

Best regards,
Nurmukhammad

Hi Nurmukhammad,

Thanks for sharing more details.

1.To analyse further, could you please let us know which BSP version you are using? Also, please confirm if you’re using the example from the following path:
<installation path>:\Analog Devices\EV-SC59x_EZ-KIT-Rel<BSP revision>\EV-SC59x_EZ-KIT\Examples\drivers\adc\Audio_Talkthrough_I2S.

2. You can set a breakpoint in the SPORT Rx callback to check if the DAC buffers are receiving data. You can view the buffers in the expressions window. To add the Expressions view to your current perspective, go to Window > Show View > Other > Debug > Expressions and click OK. For more information, refer to the following help path:
CrossCore® Embedded Studio 3.0.1 > Integrated Development Environment > Navigating Within the IDE > Views > Debug.

3.From your previous image, it seems you are using the SHARC core example. However, you have imported both ARM and SHARC examples. Please confirm whether you are using the ARM or SHARC example. If you are working with the ARM core, please add the following function before the main function and let us know the outcome:
" void adi_mmu_Init(){
      asm("nop;");
} "

4.In your hardware boot mode switch is set to 1. Please change this to no boot mode (0) and try again.

Regards,
Nandini.C

Hello Nandini,

Thank you for your detailed response.

To answer your questions:

1. I am currently working on BSP revision 4.0.
2. I followed your instructions to set a breakpoint in the SPORT Rx callback and view the buffers in the Expressions window. I’ll continue to use this approach to check if the DAC buffers are receiving data.
3. Regarding the use of either the ARM or SHARC core example, I can confirm that I am primarily working with the SHARC core. However, I will try the suggested function for the ARM core if necessary.
4. I also took into consideration the suggestion to change the hardware boot mode to no boot mode (0), and I will make that adjustment.

In the end, I swapped the input and output to other audio types, specifically using laptop audio in and speaker out, which ended up working just fine. However, when I use an oscilloscope and signal generator, I don’t get any signal.

Thank you again for your assistance.

Best regards,
Nurmukhammad