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Re: [rtl] newbie question
All of the required tasks are possible:
1) I/O: write an interrupt driven driver (or do polling if you really have to)
2) Time of the day: no problem, but how precise do you need it
3) delay microseconds: the kernel (2.x.x at least) provides a routine 'udelay'
which uses a softwareloop based on the famous BogoMips (loops/sec) to achieve
short delays, so you would need a driver for such a service.
But: A very good definition of a RT system I found in the discussions here was
something like:
'A system where the outcome of a request depends on it's input and the time of execution.'
Is this relevant for you, then you need an RTOS which assures a defined mean minimum/maximum
request/response relation.
In other words: If you need a timestamp on any I/O on you rs485, or if you have an application
which has to respond to your I/O in a defined time period, you very probably nee RT-Linux.
TF
> From owner-rtl@rtlinux.cs.nmt.edu Thu Jul 9 19:34 MET 1998
> Date: Thu, 9 Jul 1998 16:31:56 +0200 (METDST)
> From: Mental Teo <s499435@dutiwy.twi.tudelft.nl>
> X-Sender: s499435@dutiwy.twi.tudelft.nl
> To: rtl@rtlinux.cs.nmt.edu
> cc: j.landgraf@dutiwy.twi.tudelft.nl
> Subject: [rtl] newbie question
> MIME-Version: 1.0
>
> just a quick question....
>
> our program works "correctly" under dos(yuck :)
>
> the only realtime thing in it is very simple...
>
> i need to read data from a rs485 port (say what!)
> furthermore i need to know the time since midnite
> in microseconds, and i have to delay in microseconds.
>
> gettimeofday suck for that matter.
>
> my question then is:
>
> do i really need this rtlinux or not?
>
> Teo.
> +------------------------------------------+
> | Dennis Bergkamp. Holland - Argentina 2-1 |
> | Football. |
> | It's not just a game, it's an art form |
> +------------------------------------------+
>
> --- [rtl] ---
> For more information on Real-Time Linux see:
> http://www.rtlinux.org/
>
--- [rtl] ---
For more information on Real-Time Linux see:
http://www.rtlinux.org/