i.MX6DQ LDO output voltage when boot.

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i.MX6DQ LDO output voltage when boot.

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satoshishimoda
Senior Contributor I

Hi community,

I want to confirm about i.MX6DQ PMU.

I understand i.MX6DQ works 792MHz and LDO Enabled mode after iROM code is read when boot sequence, doesn't it?

Then, would you let me know the i.MX6DQ LDO output voltages (VDD_ARM_CAP and VDD_SOC_CAP) after iROM code is read?

According to chapter 50.7.4 in IMX6DQRM (Rev.2), the initial settings for VDD_ARM_CAP and VDD_SOC_CAP seem 1.100V after reset.

But these are not satisfied the operating ranges when 792MHz LDO enabled mode.

So I think the LDO voltages are changed by iROM code.

Best Regards,

Satoshi Shimoda

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igorpadykov
NXP Employee
NXP Employee

Hi Satoshi

792MHz =>1.150 V, 396MHz =>0.925 V

Best regards

igor

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igorpadykov
NXP Employee
NXP Employee

Hi Satoshi

you are right, LDO voltages are changed by iROM code.

When the system boots up, before running to ROM, the default ARM core freq is 24MHz,

and built-in ARM/PU/SOC LDOs are running at LDO-enabled mode, with

VDD_ARM_CAP = VDD_PU_CAP = VDD_SOC_CAP = 1.10V. 

When system goes to ROM, LDOs output voltages would be raised to necessary values

and the ARM core frequency would be raised to 792MHz or 396MHz (depending on the

BT_FREQ Fuse bit setting).

Best regards

igor

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satoshishimoda
Senior Contributor I

Hi Igor,

Thank you for your reply.

OK, I understood the voltages before running to ROM.

Then, would you let me know the voltage after running to ROM also?

792MHz => xxx [V], 396MHz => yyy [V]

Best Regards,

Satoshi Shimoda

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igorpadykov
NXP Employee
NXP Employee

Hi Satoshi

792MHz =>1.150 V, 396MHz =>0.925 V

Best regards

igor

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satoshishimoda
Senior Contributor I

Hi Igor,

I found the VDD_SOC_CAP voltages (1.10V@24MHz, 0.925V@396MHz) are out of operating range.

These should be 1.15V or higher.

And 1.150V@792MHz is also out of range if VPU frequency is over 264MHz then.

Best Regards,

Satoshi Shimoda

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igorpadykov
NXP Employee
NXP Employee

Hi Satoshi

VDD_SOC_CAP is used for HDMI,PCIE,SATA

they are not used by iROM and modified later.

Best regards

igor

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satoshishimoda
Senior Contributor I

Hi Igor,

Thank you for your reply.

OK, I understood the VDD_SOC_CAP voltages are no problem even if these are out of operating range on the timing.

Best Regards,

Satoshi Shimoda

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