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Visitor
Visitor
3,772 Views
Registered: ‎10-18-2013

Voltage scaling for Zynq?

Hello everyone,

 

I am trying to add some voltage scaling in the kernel (arch/arm/mach-zynq/common.c) : adding new frequencies is quite easy, but for the moment there is no support for voltage, so I am writing it myself.

 

Anyone knows what values (in uvolts) the Zynq accepts?

 

I cannot find this information anywhere.

 

Thanks,

 

Michele

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Scholar
Scholar
3,766 Views
Registered: ‎02-27-2008

m,

 

The data sheet states the range of voltage for the various supplies.  It is only specified over the +/- 5 percent range (0.95 to 1.05 v).  There is no variable voltage feature for the 28nm technology node.

 

See DS191

 

Austin Lesea
Principal Engineer
Xilinx San Jose
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Visitor
Visitor
3,739 Views
Registered: ‎10-18-2013

The information in DS191 is about the external voltage to power the chip: I was more thinking about voltage scaling inside the ARM to optimize performance/consumption depending on the processor's load without actually having to go into sleep modes.

 

I guess your answer means no fro 28nm FPGA fabrics, but this is limited to the PS, and does not concerns the PL.

 

In the Linux driver it is stated "Currently we only support frequency scaling", so it does look like voltage scaling is just a software feature not yet added!

 

Thanks,

 

Michele

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Xilinx Employee
Xilinx Employee
3,707 Views
Registered: ‎07-31-2008

The operating voltage for the Zynq PS is specified as 1.0V +/-5% for most parts and as 1.0V +/-3% for some parts (e.g. -3E speed grade). The Zynq PS was not designed to support voltage scaling in the commonly understood sense of the term but if you can guarantee to stay within the documented operating voltage requirements over your operating conditions (temperature, frequency, power supply noise, IR drop, etc) you could make some run-time adjustments. I'm doubtful it will buy you much for your power budget.

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