How to properly use DC Input Entry

Richardmy Question

May 26, 2025 00:00

Hi,

I want to use DC Input Entry to index ISF.

So, if I'm using 1467 - 32bit, according to AD Wiki I need to use integer value for ISF: 32.0

But before that I wanted to debug input value with a Readback, but it reads the wrong value and it changes only if I change format:
E.g. 32.0 = -2; 8.24 = -0.00000006;

So, I have two questions:

1. Why is Readback has a bad reading?

2. What do I need to know about using DC Input Entry with ISF?

Audio Signal Processors

Sigma Studio (Rev. 4.7)

software

DSP Readback

adau1467

SigmaDSP Audio Processors

DC Input Entry

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Harishgowtham Reply

May 26, 2025 00:00

Hello Richardmy,

I guess you have a communication problem between your PC and DSP. Make sure the USBi is properly connected and green in color in the schematic page.

You are correct that you must use 32.0 format to index the filter, so what you are doing is right, but you run into an issue somewhere else mostly hardware related issues.

Are you using an eval board or a custom board? if custom board, please share your hardware schematic.

Give the board a power cycle or open a fresh project and try again. if possible, send us a picture of your setup.

It seems like the core isn't running, just check if the DSP is programmed and running. Probe any of the serial port clocks and see if the clocks are coming out, by default all ports are set as master and you can see clocks going out if the DSP is properly programmed from SS.

The SS 4.7 has no problem with a DC cell and a readback, so it must be something related to hardware/communication.

Feel free to reach out after you checked all this.

Regards,

Harish

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Richardmy Reply

May 26, 2025 00:00

Yes thanks, It was a connection problem. I forgot to change to my second setup where I use i2c instead of spi for debugging =)

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