Re: [linux-sunxi] Re: [U-Boot] [PATCH] sunxi: set the default CPUx frequency of H5 to 816MHz

[Jagan Teki]

On Wed, Nov 1, 2017 at 7:40 AM, Ondřej Jirman  wrote:
> Hi,
>
> Icenowy Zheng píše v St 01. 11. 2017 v 08:31 +0800:
>>
>> And according to the Orange Pi PC2 and Prime schematics, they both
>> start at 1.1V. (The Prime schematics even says "For H5 adjust
>> VDD-CPUX to 1.1V).
>>
>
> Orange Pi PC2 starts at the same voltage as Orange Pi PC. That is at
> 1.308V.
>
> It can be calculated from 0.6×(1+11.8÷10) as per the values of Ru1/Ru2
> resistors in the schema. It is also my experience of working with these
> boards and writing the sy8106a driver.

I think you reverse the Ru values according to pc2 and prime schematic
 CPUX Vout = 0.6x(1+Ru1/Ru2)

so Ru1 10K and Ru2 11.8K then Vout = 0.6x(1+10/11.8) => 1.10V

thanks!
-- 
Jagan Teki
Free Software Engineer | www.openedev.com
U-Boot, Linux | Upstream Maintainer
Hyderabad, India.

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Re: [linux-sunxi] Re: [U-Boot] [PATCH] sunxi: set the default CPUx frequency of H5 to 816MHz

['Ondřej Jirman' via linux-sunxi]

'Ondřej Jirman' via linux-sunxi píše v St 01. 11. 2017 v 03:10 +0100:
> Hi,
> 
> Icenowy Zheng píše v St 01. 11. 2017 v 08:31 +0800:
> > 
> > And according to the Orange Pi PC2 and Prime schematics, they both
> > start at 1.1V. (The Prime schematics even says "For H5 adjust
> > VDD-CPUX to 1.1V).
> > 
> 
> Orange Pi PC2 starts at the same voltage as Orange Pi PC. That is at
> 1.308V.
> 
> It can be calculated from 0.6×(1+11.8÷10) as per the values of Ru1/Ru2
> resistors in the schema. It is also my experience of working with these
> boards and writing the sy8106a driver.

Anyway, I may be mis-remembering in the case of PC2. So please ignore
me. :) I'm only sure in the case of Orange Pi PC, which is not relevant
here. Sorry.

> regards,
>   Ondrej
> 
> > > 
> > > There's no need to enforce a SoC-wide change.
> > > 
> > > Maxime
> > 
> > 
> 
> 

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Re: [linux-sunxi] Re: [U-Boot] [PATCH] sunxi: set the default CPUx frequency of H5 to 816MHz

['Ondřej Jirman' via linux-sunxi]

Hi,

Icenowy Zheng píše v St 01. 11. 2017 v 08:31 +0800:
> 
> And according to the Orange Pi PC2 and Prime schematics, they both
> start at 1.1V. (The Prime schematics even says "For H5 adjust
> VDD-CPUX to 1.1V).
> 

Orange Pi PC2 starts at the same voltage as Orange Pi PC. That is at
1.308V.

It can be calculated from 0.6×(1+11.8÷10) as per the values of Ru1/Ru2
resistors in the schema. It is also my experience of working with these
boards and writing the sy8106a driver.

regards,
  Ondrej

> > 
> > There's no need to enforce a SoC-wide change.
> > 
> > Maxime
> 
> 

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