Try downloading miniRTLinux from: www.fsmlabs.com.
It runs Linux from a series of ram disks instead of the hard disk. This
means that no jitter will be introduced into your measurements from the
hard disk. By default the networking is disabled so the network card in
your machine will not introduce any additional jitter.
Read the documentation.
Installing it on a floppy involves the following steps:
download it
move to floppy using 'dd' as stated in the documentation
boot from the floppy
Read the documentation on how to put your own code on the same floppy.
- Kal.
Bart Vandewoestyne wrote:
>
> I have built a PCB to read the value of an analog voltage by using the
> parallel port. The circuitry uses a Dual Slope A/D conversion. In
> order to make that conversion, I have to count how long a certain
> time-interval is. Therefore I generate a square wave of 109 kHz and try
> to count that with the parallel port, this is what I do:
>
> --> I set one bit of the parallel port, say A, high (for visualisation
> on an oscilloscope)
>
> --> then I need to count 10000 pulses, i do it with the following
> C-routine:
>
> void count(int time)
> {
> int value = 0;
> int clock
>
> while (value < time) {
> do
> {
> clock = inb(BASEPORT+1) & 0x80;
> }
> while (clock == 0);
>
> do
> {
> clock = inb(BASEPORT+1) & 0x80;
> }
> while (clock == 0x80);
>
> waarde++;
> }
> }
>
> --> Then I set the bit A back to zero.
>
> So, that means that every time i call the function count(10000) I should
> always see the same HIGH-time for bit A, and that's not what happening!
> The HIGH-time for A isn't a constant. I have also written a similar
> program for the DOS environment and there it works just fine. My
> question is: how should I solve this problem in order to have the same
> HIGH-time every time i invoke the count(10000) function? How can i make
> my analog voltage measurements more reliable? Is real time linux the
> solution or do there exist shorter and easier ways?
>
> I would like to mention that I'm a student and Real Time Linux is
> totally new for me, so if there are easier ways to achieve my goal then
> i would like to know. If Real Time Linux is the only solution for my
> problem then please explain me how I should change my program or how i
> should set things up.
>
> Thanks a lot!
> Bart Vandewoestyne, engineer electronics student.
>
> --
> Bart Vandewoestyne http://hello.to/MC303
> Hugo Verrieststraat 48 [EMAIL PROTECTED]
> 8550 ZWEVEGEM ICQ# 21275340
> BELGIUM - EUROPE nick: MC303
> Phone: +32(0)56/75.48.11
> -------------------------------------------------------------
> "Der Horizont vieler Menschen ist ein Kreis mit Radius Null -- und das
> nennen sie ihren Standpunkt."
>
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