Re: Volunteers for small coding job?

[Sami T. <fl...@ee...>]

On Mon, Apr 25, 2005 at 04:21:13PM +0800, Wai-Sun Chia wrote:
> On 4/24/05, Sami Tapio <fl...@ee...> wrote:
> > Hello,
> > 
> > I need a volunteer for small coding project, as it happens that I'm
> > totally C illiterate... I think that this might be quite easy
> > modification from the LIRC project sources. Brief description:
> > 
> > I need a kernel module that reacts on parallel port IRQ, reads 4
> 
> You don't need a kernel module to access the parallel port.
> A regular userspace program would do.
> Please see below for a very good summary:
> http://www.faqs.org/docs/Linux-mini/IO-Port-Programming.html

From what I've learned from reading various documents, including the 
one on your link above, I need a kernel module. Because I need a fast 
reaction on the IRQ... with this slow HW I can't afford the 
scheduling losses. Or to use polling to find out if the pins have 
changed states or not. If I have understood this correctly, even to 
get something happening on parallel port IRQ, I need a kernel module.

So kernel module it is. :)

> 
> > input pins state and record those states and the time of the IRQ
> > to a file. Time should be atleast 1ms or smaller. And some method
> > of getting a output to one pin in parallel port at desired time.
> 
> A daemon would do it.
> 

Actually, the user would start the sequence of things when needed and 
that would result in a output pulse on one of the parallel port pins, 
getting the HW running and then there would be nothing to be done before 
the IRQ gets the states of the input pins read to a file. After couple 
of IRQs, the user (actually bash script) would remove the kernel module 
and start to interpret the pin changes from the file. So, I don't know 
how it could be easily done in the C-code, so that I could make a bash 
script to get the kernel module to toggle the output pin... Well, 
this is the headache of the volunteer, if I find one.

Flexy