Question about how to automate power-up sequence.

[hikaruuruno]

Hi Community,

We are planning to make a custom board with DCDC_BATT source only configuration which will power-up automatically when the power is supplied.

There are description in the documents of i.MX28 that in case of DCDC_BATT source only configuration, PSWITCH pin must be around MID level for 100ms to power up the IC.

Also, there is a description that "A MID LEVEL PSWITCH state can be generated by connecting the VDDXTAL output of the SoC to PSWITCH through a switch."

I suppose the part "through a switch" is to control power-up manually.

So, is there no problem to connect PSWITCH and VDDXTAL directly to automate power-up?

I could not find the exact same question in the community but if there is one and I just missed it, please redirect me to it.

Thank you in advance,

Hikaru

[igorpadykov · Accepted solution]

Hi Hikaru

you are right, one can connect VDDXTAL via 1K to PSWITCH.

This triggers the startup automatically.

Best regards

igor

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