Does the Nois ii processor support DVFS(dynamic frequency and voltage scaling)?

[Altera_Forum]

Hi, 

:p  I am doing research about power management.Now I want to create a distributed system envinronment using Nois ii on Cyclone iii.   But my question is " Does the Nois ii processor support DVFS?" If so,can I use MicroC/os to change the frequency at runtime?:D    If not,would other processor on the Cyclone iii support? But I think in that case,I need to buy the IP.Right?:mad:    Is there anyone here also doing the same thing?Thanks very much:cool:

[Altera_Forum]

Hi, 

 I am also doing research about power management. I also have the same question. Please reply if you find information.  I think we can have multiple PLLs in NIOS ii based systems and Operate the system at different frequencies. I have DE2 FPGA board with cyclone II FPGA.

[Altera_Forum]

--- Quote Start ---  Hi,  I am also doing research about power management. I also have the same question. Please reply if you find information.  I think we can have multiple PLLs in NIOS ii based systems and Operate the system at different frequencies. I have DE2 FPGA board with cyclone II FPGA.  --- Quote End ---    Hi,  Generally speaking, you can change the frequency but can not change the voltage. Please check my paper "An FPGA-based Distributed Computing System with Power and Thermal Management Capabilities"

[Altera_Forum]

Thanks for the reply, I ll look into your paper and ask more if required, 

Can you tell me if I can control the PLLs on my DE2 board( Cyclone II FPGA) through software to switch between different frequencies. If yes, how can I measure the switch-over delay ( Time it takes to switch from a frequency to other) and meanwhile to keep the state of the processor harmless, we need to stall the CPU ?  I have Implemented already an H.263 encoder on a NIOS ii based system and now I want to invlove these frequency switchings and check the performance variations between the Implementation (without DFS) and with DFS. I am also interested in Power Consumption measurements of the NIOS ii based systems. I have never done any power consumption measurements before.   SO i look forward to suggestions from your side for up mentioned work. Some ideas to set my action plan further. I think we cant switch between different voltage? Is there FPGA device by ALTERA supporting voltage switching of designed circuits??  Thank you very much.

[Altera_Forum]

--- Quote Start ---  Thanks for the reply, I ll look into your paper and ask more if required, Can you tell me if I can control the PLLs on my DE2 board( Cyclone II FPGA) through software to switch between different frequencies. If yes, how can I measure the switch-over delay ( Time it takes to switch from a frequency to other) and meanwhile to keep the state of the processor harmless, we need to stall the CPU ?  I have Implemented already an H.263 encoder on a NIOS ii based system and now I want to invlove these frequency switchings and check the performance variations between the Implementation (without DFS) and with DFS. I am also interested in Power Consumption measurements of the NIOS ii based systems. I have never done any power consumption measurements before.   SO i look forward to suggestions from your side for up mentioned work. Some ideas to set my action plan further. I think we cant switch between different voltage? Is there FPGA device by ALTERA supporting voltage switching of designed circuits??  Thank you very much.  --- Quote End ---    Hi,  I do not know your board. But my previous work works on my board(NEEK with CYClONE III).  When I did the research , I remember there is an IP in the tool (called clock reconfiguaration or something else). You can use it together with PLL in the Quartus tools to change the frequency safely. It can be controlled by processor's IO pins which can be set in your software. Then the output can feed the clock pin of the processor.But I did notice the delay was big. So I used my own way(Please check my paper). Yes, definitely you need to concern about the glitch problem during transition.  For the voltage part, I am not sure. I do not know any board supporting voltage change.  For the power measurement, I didn't measure the power before. I think maybe there are jumpers you can use or maybe you can just measure the current of the board's power supply. But I assume you will not see much power savings because:(1)You can not scale voltage;(2)FPGA is not that power intensive compared to real processor or ASIC;(3) Softcore processor's power might be a small part of the whole board's power.

[Altera_Forum]

FPGAs are not at all comparable to DSPs or other processors on the power utilization grounds because of the parallelism. And I have also worked on FPGAs for my image processing project, you can only change the frequency and not the voltage. You need to add extra circuitry manually on your board if you want to change voltage during runtime in your program.