I.MX28 Custom HW hangs at power initialization

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I.MX28 Custom HW hangs at power initialization

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joelk
Contributor II

I am having trouble bringing up my custom board based on the i.MX28 EVK. I have inserted print functions in the boot code to see where it fails. I'm using sb_loader to boot from USB. it hangs after PowerPrep_Init4p2Regulator(); line 725 in power_prep.c


My hardware follows the VDD5V only setup as outlined in AN4199

We have unmarked NO_DCDC_BATT_SOURCE and marked out NO_VDD_SOURCE in power_prep.c


Question 1: Are there other code changes that I need to make to support VDD5V only configuration?

Question 2: I notice that I have left the TESTMODE pin C10 floating. Is this a likely cause of the hang? I have marked this line to be tied low for the next PCB revision.


Attached are my power_prep.c and hardware checklist


Any help is greatly appreciated.

Original Attachment has been moved to: power_prep.c.txt.zip

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igorpadykov
NXP TechSupport
NXP TechSupport

Hi Joel

you are right TESTMODE should  be tied to ground, otherwise

chip can enter to test mode.

You can further add debug printf for locating accurate operand:

this would be brownout cause and then you can add time delay or

increase brownout level.

All necessary patches are given below

Updates and Patches (9)

i.MX28 Evaluation Kit|Freescale

Best regards

igor

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igorpadykov
NXP TechSupport
NXP TechSupport

Hi Joel

you are right TESTMODE should  be tied to ground, otherwise

chip can enter to test mode.

You can further add debug printf for locating accurate operand:

this would be brownout cause and then you can add time delay or

increase brownout level.

All necessary patches are given below

Updates and Patches (9)

i.MX28 Evaluation Kit|Freescale

Best regards

igor

View solution in original post

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joelk
Contributor II

We had our local assembly shop modify the PCB to tie Testmode low before placing the BGA. Our boards now get all the way through power initialization without any problem. I still am not able to boot all the way to uboot prompt but I will start a new thread because it is a RAM problem now.

Thank you for the help

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joelk
Contributor II

Hi Igor, thanks for your reply.

We have already applied the patches. I will try adjusting the brownout level.

How can i tell if the chip has entered test mode? Is there an obvious change in the chips behavior that I can watch for to make sure this isn't happening?

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igorpadykov
NXP TechSupport
NXP TechSupport

Hi Joel

sorry details about test mode are not available,

this mode is only for factory testing.

~igor

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