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ADS8557: First read data is wrong

Part Number: ADS8557

After A/D conversion (BUSY = L), I read datas by Parallel Read Access (Figure 3 on SBAS404D –OCTOBER 2006–REVISED FEBRUARY 2016).
I turn CONVST_x to L after BUSY=L. CONVST_x is L to next data conversion.

CS is activated for each data read, not continuous. Read access timing is the same for all read access.

Sometimes first data is worng. Followings are datas when first data is wrong.

1st Data - wrong CH A0 data

2nd Data - correct CH A1 data

3rd Data - correct CH B0 data

4th Data - correct CH B1 data

5th Data - correct CH C0 data

6th Data - correct CH C1 data

7th data - correct CH A0 data

It seems A/D conversions are correct and only first data read access failed.

Why  is first read data wrong sometimes ?

  • Hello,

    Would you share what mode you are using the device in?  Would you share more detail about how the data is wrong?

    Also, would you collect a scope shot of the digital communication of the wrong and right data, this would be helpful to eliminate any timing discrepancies

    Regards

    Cynthia