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[ts-7000] Re: Write to memory without mmap()?

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Subject: [ts-7000] Re: Write to memory without mmap()?
From: "Simon" <>
Date: Mon, 19 Jul 2010 13:35:48 -0000
Thanks WouterS and Jim Jackson. Now I understand a little better what's going 
on in there.

My problem is that I'm trying to do some very fast communications through the 
SPI port and I need to do some flag management through the DIO ports. I've done 
some tests and when I go beyond 8 kHZ it seems that the kernel gets in the way 
and creates small delays in the process.

I was trying to get past that by communicating straight to the hardware. I've 
read about something called 'nice' to increase the priority of my program but I 
don't know how to use it for the TS boards. Can someone point me to 
documentation or tell me how it's done?

Thank you very much for your help!

--- In  Jim Jackson <> wrote:
>
> 
> 
> 
> On Thu, 15 Jul 2010, Simon wrote:
> 
> > Hi, I've been using the peekpoke instructions as inline assembly and they 
> > work perfectly. However, I was wondering if there's a way, using inline 
> > assembly, to use these functions without mmap'ing. Maybe set some flags 
> > that'd let me control the memory locations directly?
> >
> > I just want to be able to communicate with the GPIO ports directly 
> > instead of having to go through virtual memory mapping. Is there a way to 
> > do this?
> 
> Not without having to go through virtual memory mapping.
> You can do it without using peekpoke functions.
> Once you have addresses mmap'ed, or addresses calculated from mmap'ed base 
> addresses, you can use them directly. There is example code around.
> If stuck check out the ts7200.c file in any of my programs.
> 
> 
> cheers
> Jim
> ----------------------------------------------------------------------------
> HomePage:    http://www.comp.leeds.ac.uk/jj
> TS7200 Page: http://www.comp.leeds.ac.uk/jj/linux/arm-sbc.html
>




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