IMX28 VDDIO voltage differs from setting

[davidrabe]

The iMX28 generated VDDIO is on all of our boards 3.4V, although the 8004_4060(hex) register is set via software to 0004230a(hex).

VDDA and VDDD however have exactly the voltage that I expect based on the respective register values​​.

Does anybody know where this VDDIO deviation come from? Thank you.

For completness:

Absolute address (hex): Value(hex)

8004_4000: 00018024

8004_4010: 20308593

8004_4020: 00000040

8004_4030: 00010000

8004_4040: 0002071c

8004_4050: 0000270c

8004_4060: 0004230a

8004_4070: 00000230

8004_4080: 00000018

8004_4090: 00000000

8004_40a0: 0000305f

8004_40b0: 00167021

8004_40c0: 01141210

8004_40d0: 0000ff00

8004_40e0: 01f90e0f

[igorpadykov · Accepted solution]

Hi David

the output accuracy of the switchers is +/- 3%.

So programming as 3.3V (TRG=0xA) one can get 3.4V ( 3% deviation).

One can program voltage value with one step less.

Best regards

chip

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