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[ts-7000] Re: high resolution timers and real time

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Subject: [ts-7000] Re: high resolution timers and real time
From: "komal" <>
Date: Mon, 02 Apr 2012 07:39:22 -0000
Dear Sir,

I have recently acquired a ts-7500 board with the development kit. The SD card 
comes with a 2.6.24 Linux Kernel. After a few days of experimenting I have 
realized that my application (controlling a servo through PWM) will require HRT 
and RT support which the Kernel is unable to provide (maximum timer resolution 
I am getting on the current Kernel is 20ms). 

I am new to Linux and embedded systems development and hence I am a little 
confused about how to tackle this problem. I do not understand what you mean by 
applying the patches and how to apply the patch. Can i simply do it on-board my 
board with the SD-Card. I have a windows PC with Eclipse for Development.

Any help you can provide me will be highly appreciated. Thank you.

Regards,
Komal RAUF

--- In  Peter Gammie <> wrote:
>
> Charles, any anyone interested in hrtimers:
> 
> With Andrew's help I managed to build a 2.6.32.3 kernel that seems to work. 
> Attached are a config and a patch, based on this:
> 
> http://lkml.org/lkml/2009/7/22/119
> 
> that enable hrtimers. I've lightly tested it on a ts7260 with 64Mb of memory. 
> I loaded the kernel via TFTP with:
> 
> load -r -b 0x00218000 -h 192.168.1.1 z
> exec -c "console=ttyAM0,115200 
> ip=192.168.1.50:192.168.1.1:192.168.1.1:255.255.255.0:ts7200a:eth0:off  
> root=/dev/mtdblock1"
> 
> (i.e. no special memory options or anything.)
> 
> So the routine is to apply Matthieu's patches, then this one. I expect it 
> will apply to other kernel versions (specifically 2.6.29.6 if you want -RT) 
> without too much bother - but be careful that the Kconfig patch applies to 
> the right system type!
> 
> As for the clock multiplexing, Charles's suggestion of using just a PREEMPT 
> (not RT) kernel results in better behaviour under light periodic load (it 
> doesn't flicker while running top on the console) but about the same under 
> heavier load (scp'ing a few megabytes via ethernet). I have the CONFIG_NO_HZ 
> (tickless) option set, which may or may not do anything in particular...
> 
> So, more investigation is required.
> 
> Thanks for all your help.
> 
> cheers
> peter
> 
> 
> 
> 
> -- 
> http://peteg.org/
>




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