[fpc-pascal] spin_lock

[Marc Santhoff]

Am Dienstag, den 30.05.2006, 16:24 -0400 schrieb Alain Michaud:
> I use one of those (ISA) I/O bards: I write or read from a port and
> control a "slow" experiment. More details about the timing:    

IMO this is your main problem: the rotten old board. ;)

To get away from "dangerous programming" I personally would solve it by
using an I/O-Board that drives Interrupts on the host computer. Even
cheap ones are able to make 1 ms timing.

Another hardware based solution would be to connect a microcomputer
board inbetween the computer and the sensor stuff. A little AVR or
similar can easily programmed to get one trigger command and then read
in values at 1ms timing for 200ms. Afterwards it can transfer data to
the host.

> THE PROBLEM...
> 
>  The problem: the problem is: even if the timing is not so critical and
> the the experiment does not last for long, once it has started then the
> processor should not leave and go answer the phone for another
> process... I think that most process can be delayed for 200ms but my
> acquisition loop should NOT be interrupted while it is doing its thing.

If the measure is extremely critical, why does the computer have other
tasks to do? Can't you use a dedicated machine for the measurement?

HTH,
Marc