cpu freq change problem bringing up new i.MX28 board

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cpu freq change problem bringing up new i.MX28 board

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iMxGuy
Contributor II

Hi,

I am working on bringing up a new i.MX28 board we designed and the last output I get during the boot process is "start change cpu freq". As far as I can tell by looking at the boot_prep code is that the cpu frequency is being changed after this message is printed. I do not get any other output after this message and the board seems to freeze. Any ideas on what could be the problem? I am using the standard bootlet code from version 10.12.01 without any changes.

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iMxGuy
Contributor II

I found the problem in case anyone else runs into this issue. Our new hardware does not run on battery so the missing voltage on the battery input pin was causing the power_prep initialization to fail. We modified the power_prep.c file to ignore the voltage on the battery input.

 

***************
*** 646,652 ****

HW_POWER_DCDC4P2.B.TRG = 0;
HW_POWER_5VCTRL.B.HEADROOM_ADJ = 0x4;
! HW_POWER_DCDC4P2.B.DROPOUT_CTRL = 0xA; //100mV drop before stealing
// charging current
HW_POWER_5VCTRL.B.CHARGE_4P2_ILIMIT = 0x3f;
}
--- 670,676 ----

HW_POWER_DCDC4P2.B.TRG = 0;
HW_POWER_5VCTRL.B.HEADROOM_ADJ = 0x4;
! HW_POWER_DCDC4P2.B.DROPOUT_CTRL = 0x8; //100mV drop before stealing //was0xA
// charging current
HW_POWER_5VCTRL.B.CHARGE_4P2_ILIMIT = 0x3f;
}

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