So, the jitter of about 10us that I saw wasn't a oscilloscope problem.
Unfortunately, it was caused by RTAI.
But I found something very interesting: when I code the same program in the
user-space, the older was coded to be a kernel module, I could achieve a jitter
less the 5us!
So I realized what I need right now: to know some good practices in RTAI
programming :)
Does anyone can give me some advice?
Thanks,
Ronan.
--- In "ronis_br" <> wrote:
>
> Hi everyone,
>
> First of all, I would like to thanks everyone who have helped me!
>
> I finally could make RTAI works! The problem: I used a wrong gcc version to
> compile the kernel. I was using gcc-3.4.4 but the TS 2.4 kernel must be
> compiled with gcc-3.3. After this, everything works fine.
>
> Now I'm testing RTAI.
>
> I'm beginner in kernel modules programing so I need some help.
> I realized that I couldn't use the functions open, mmap and so that TS uses
> in examples to access the registers. Than I found that I can do this using
> the function outb(value, address). Everything works fine, but is this the
> right thing to do?
>
> I could construct the wave form that I want, but I'm seeing on oscilloscope
> some oscillation of about 20us that happen randomly. I can't really say if it
> is because RTAI or the oscilloscope problem. I'm investigating and when I
> have a conclusion I'll post here.
>
> Some interesting point: to test RTAI, I maid a square wave by software (a
> kernel module). I saw that if the period of this wave is less than 50us,
> approximately, than the system locks :D The wave continues to be executing,
> but there is seems to be no more time to linux tasks, so I can't use it
> anymore by serial.
>
> Thanks everyone one more time,
> Ronan.
>
> --- In sjanisch@ wrote:
> >
> > I didn't set support for JFFS2. Isn't that more of a file system entry
> > (I'm not a real linux expert by any means... more of a hack than
> > anything)?
> >
> > The flash stuff that I was talking about was in this section
> > #
> > # Memory Technology Devices (MTD) for 2k NAND flash
> > #
> > CONFIG_MTD2K=y
> > # CONFIG_MTD_DEBUG is not set
> > CONFIG_MTD_PARTITIONS=y
> > # CONFIG_MTD_CONCAT is not set
> > # CONFIG_MTD_REDBOOT_PARTS is not set
> > # CONFIG_MTD_CMDLINE_PARTS is not set
> > # CONFIG_MTD_AFS_PARTS is not set
> > CONFIG_MTD_CHAR=y
> > CONFIG_MTD_BLOCK=y
> > # CONFIG_FTL is not set
> > # CONFIG_NFTL is not set
> > # CONFIG_INFTL is not set
> >
> > Assuming the 7260 and 7250 use the same flash (which I couldn't tell
> > you)... this was the missing step in getting the flash to work.
> >
> > But I think they do. The TS-7200 lists the flash as NOR flash, while the
> > 7250 and 7260 list NAND flash.
> >
> > From what I understand, this is the actual driver that allows the kernel
> > to read the flash...
> >
> > I'll send the complete .config file to your gmail account... note that it
> > was for the 7250 rather than the 7260, but the two appear pretty close in
> > terms of specs.
> >
> >
> > wrote on 08/03/2009 01:59:24 PM:
> >
> > > With your procedures, I could compile the kernel correctly, but I
> > > just can do it when I disable the support for CONFIG_JFFS2_FS_NAND.
> > > But the system cannot boot correctly if I have this option disable in
> > kernel.
> > >
> > > When I try to compile it with NAND support for JFFS2 enable, than I
> > > get the following error:
> >
>
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