About VPU clock at 352MHz in i.MX6DQ.

[keitanagashima]

Dear All,

I have known it is possible to change the VPU clock up to 352MHz by kernel menuconfig in i.MX6DQ.

When changing the VPU clock, what influence is there?

- Is only the operation clock of VPU changed?

- Is the voltage of internal LDO changed? (It need to change the voltage)

- Is setting changed into the others?

- Is there a demerit?

(For example, current consumption is increased. Do you have the data of current consumption at VPU:352MHz)

Best Regards,

Keita

[igorpadykov]

Hi Keita

-Is only the operation clock of VPU changed?

yes

-- Is the voltage of internal LDO changed? (It need to change the voltage)

yes it changed according to datasheet

-- Is setting changed into the others?

no

-- Is there a demerit?

power consumption may be increased, some figures can be found

in AN4509 sect.3.7 Typical Max Power

Best regards

igor

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[keitanagashima]

Dear Igor,

Hello. We had found the below impact.

When the user changed the VPU clock to 352 MHz by kernel menu config, PLL2_PFD2 from 396 MHz to 352 MHz, then the uSDHC1_CLK_ROOT~uSDHC4_CLK_ROOT and ARM core clock at stop mode had used PLL2_PFD2, too.

So, the user want to avoid this impact.

[Question]

Is it possible to change  the VPU Clock into PLL2_PFD0?  [PLL2_PFD2 --> PLL2_PFD0]

Is there some impact?

(We checked the PLL2_PFD0 is used for nowhere before the setting VPU=352 MHz.)

Best Regards,

Keita

[igorpadykov]

Hi Keita

please create new thread, as this is new problem.

Also please provide additional data:

1. full part number of processor

2. full name of BSP (web link)

3. what board is used in the case: customer board or FSL reference board (full name)

Best regards

igor

[keitanagashima]

Hi Igor,

OK. I created the new thread.

Thanks.

Best Regards,

Keita