Renner Johannes wrote:
> Hello everyone,
>
> The outb functions to control parallel ports in my user mode RT task
> causing inacceptable jitter and make the task unstable(-110) at
> higher(10khz) output frequencies. I believe this is due to mode
> switches form Primary to the Secondary mode.
You "believe" ?! You can check what happens using the same method as
ksrc/skins/native/snippets/sigxcpu.c
> I tried to access the
> ports via /dev/mem and mmap() (method from
> xenomai/examples/common/hw_direct_io.c) but thus mapping is
> successful, writing -whatever- to the mapped pointer does not set any
> IO's on my x86.
memory mapped I/O and inb/outb belong to different spaces.
I have read that some Xenomai RT testing with the
> Parallel port at frequencies above 200khz showed excellent
> results. Which functions are used for such precise timings and are
> they only available in kernel space?
Most functions available in kernel-space are available in
user-space. Check the API documentation.
>
> Thanks in advance
>
> Johannes
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> <P><FONT SIZE=2>Hello everyone,<BR>
> <BR>
> The outb functions to control parallel ports in my user mode RT task causing
> inacceptable jitter and make the task unstable(-110) at higher(10khz) output
> frequencies. I believe this is due to mode switches form Primary to the
> Secondary mode.<BR>
> I tried to access the ports via /dev/mem and mmap() (method from
> xenomai/examples/common/hw_direct_io.c) but thus mapping is successful,
> writing -whatever- to the mapped pointer does not set any IO's on my x86.<BR>
> I have read that some Xenomai RT testing with the Parallel port at
> frequencies above 200khz showed excellent results. Which functions are used
> for such precise timings and are they only available in kernel space?<BR>
> <BR>
> Thanks in advance<BR>
> <BR>
> Johannes</FONT>
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>
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Please no html.
--
Gilles Chanteperdrix.
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