Re: Working ... but not quite

[Jon Elson <elson-at-pico-systems.com>]

Ray Henry wrote:

> List
>
> Let's get everything we know about the ini file to Robin.  Go to his site
> and see what needs to be filled in or expanded.
>
> Robin
>
> Thanks for the kind offer to help with documentation.  Yes I think that
> it will be useful.  I'm sure that the faster the pc the faster it can
> spit out pulses but I don't think that there is a 1 to 1 correlation.
> I've been content with the thought that the relationship was ordinal.
> Perhaps we should do some testing.

Well, the ISA parallel port is limited by the ISA bus, even on many
motherboard
parallel ports.  But, it isn't all THAT slow!  It should be possible to spit
out
step pulses at a rate of 100,000 per second, EASILY, with a standard
parallel port and a 100+ MHz Pentium.  Of course, OTHER parts of the
software get in the way, and the timing resolution of the pulses will suffer

at the top end.

So, I suspect, up to 50,000 step/sec, at least, the ISA timing on the
parallel
port is NOT a factor.  The trajectory and pulse generation is responsible
for
substantial overhead.  There are other schemes to get faster pulse streams,
but they all have limitations.  The problem is that tying up a CPU to time
out
pulses is a really poor way to use a CPU.

Jon