ADS125H01: ADC Data Is not True.

Hi Sedef Küçükçakaloglu,

Can you please explain what you mean by "my ADC data is always wrong"? What signals are you applying to the ADC inputs, what data are you expecting to receive, and what data do you get? Is the data completely wrong (e.g. you input 10V and the ADC data is 2.3V)? Or is there just some inaccuracy (e.g. you input 10V and the ADC data is 9.6V)?

You said you wrote all registers and read them back - can I assume that means the RREG and WREG is working correctly? And the only issue you are having is with the data?

-Bryan

Hi Bryan,

Thanks for your fast reply. You can look at my screenshots ı wrote all registers and read them and yes there is no problem with rreg and wreg. But as you can see some registers CRC values are not true is it a big problem ? I calculated CRC values with excel provided from TI. My data is complety wrong for example  My input is 3.3 volt read data is -1.7 volt you can look which data ı read from ADC. When these photos taken adc input was 0 volt. HVAVSS -15 HVAVDD 15V

so Vcm is 15-15/2 == 0.

Hi Sedef Küçükçakaloglu,

Do you have any delay between CS low and first SCLK rising edge, as well as last SCLK falling edge and CS high? I cannot tell from your screenshots but it looks like these are coincident. This violates the H01 timing restrictions in Section 7.6. If you do not have these delays, please add them to ensure the data can be retrieved successfully

Also I only see one data capture in all of the logic analyzer plots you have sent (copied below). What is the input in this case? You mentioned that your input data is 3.3.V and then also that the input was 0V, so it's not clear to me which is correct

Can you also send your register settings? I know I can figure them out from the captures you sent, but it would be easier if you can just send a list 

-Bryan

Hi Bryan,

Yes I have delay between cs and sclk. Higher than 50 ns. My input voltage 0 V. My register settings are nearly default just I have status byte on RDATA data.

Hi Sedef Küçükçakaloglu,

Can you send me the .sal file for multiple data reads? Power up the ADC, leave all registers at their defaults, then take 100 samples and provide that in a .sal file. I will review

You will have to add a file extension as for some reason sharing .sal files on e2e causes problems. So if your file is xxx.sal, please change to xxx.sal.xlsx, and then attach this file. I will remove the .xlsx extension and then can view your file

-Bryan

Hi Bryan,

I have added my record. I did it like you said.

https://drive.google.com/file/d/1h5aLhI6fcj6jB9jR0RXlzlQVjFC0bEUX/view

Hi Sedef Küçükçakaloglu,

We cannot access google drive due to our firewall, you can just insert the file in the manner I specified and it will work. Click Insert->Image/video/file

-Bryan

ads.sal.xlxs.sal.zip

Hi Bryan,

Here you go;

Hi Sedef Küçükçakaloglu,

Thanks for providing this information, I was now able to access the .sal file. To be clear, this data represents the default settings, correct?

I ask because the data you sent doesn't make much sense to me. I plotted it as shown below, and it's all over the place from -FS to +FS. It truly just looks like random data

Are you sure you have all of the connections correct between your board and the controller? I saw lots of flywiring in the image you sent, it's possible something like a ground connection is wrong. That's the only thing I can think of to explain what is shown below

Can you share a schematic?

-Bryan