Re: Alternative IO cards

[John Sheahan <jrsheahan-at-optushome.com.au>]

Hi Peter

fiber makes sense in a noisy environment. Its very possible 
one of the new firewire on fibre standards would be a
reasonable choice. or a dedicated ethernet connection.

I guess I'm thinking over a longer timefrme here. ISA is close to
unobtainable now at volume computer prices. PCI (which flavour) will
follow in a few years. 

USB can  actually offer guaranteed bandwidth and latency, unlike most
tcp implementations I've looked at.  unless I've misread the pieces of
spec I've seen.    As mentioned prior, the way I'm heading is 
to offload the relatively small hard real time part.

I'm not doing this application professionally, but thats not uncommon
for a lot of open source things.  And I sure would feel bad about
building ISA or parallel port control into a professional product
today :)

PCI involves opening up the case and using a spare slot. That
precludes some related applications I see. 

regards, john

On Wed, May 29, 2002 at 06:59:56PM -0400, Peter Cook wrote:
> 
>  wuld think that PCI would be a much more reliable and less driver intensive
> route for machine control. How can you plan real time on USB? you would be
> better off looking at realtime TCP/IP and be using industrial type devices.
> Or - to make something other than hobby - Sercos (a bit pricy...) is a very
> clean (fiber loop) method for talking to drives - just make sure you use
> Sercos and not someones attempt at a propritary sercos...
> 
> Pete
> 
> Subject: Re: Alternative IO cards
> 
> 
> >
> > Hi Paul
> >
> > yes - thats the intel/microsoft published goals to make
> > boxes cheaper / better.  6 PCI slots seems common.
> >
> > serial and parallel can be reinstated externally with usb adapters.
> > As long as the SW can cope with the drivers.
> > I note too that usb parallel cables (ie a parallel port at the end of
> > a usb interface) seem to not hold data valid.  I have not yet checked
> > to see if s simple latch (on strb) fixes this for the data port.
> > Shall do soon. need it for my current PIC programmer.
> >
> > I'm sure that clever motor control boards for PCI will be/continue to
> > be available, but I'd like to see this complemented with lower cost
> > stuff for hobby machines like mine. Probably USB based.
> >
> > I'll design and test the hardware but I'd need software assistance
> > bolting the drivers to EMC.   Should be a candidate for Fred's
> > proposed site.
> >
> > Just slowly starting to get up to speed with options for the
> > USB side of things.
> >
> > Also - thought strikes me that modules like freqmod may suffer.
> > Due to the delays in software layers between the rt module and the port
> pin.
> > One solution would be to offload much of the real time behaviour to
> > the external interface.
> >
> > Any thoughts as to how much to aim for here?
> >
> > regards, john
> >
> >
> > On Sun, May 26, 2002 at 09:29:34AM -0400, Paul wrote:
> > >
> > >
> > > Hi John
> > >
> > > Just come back from a local computer fair - It is not just ISA slots
> that are
> > > disappearing. One motherboard on sale had USD, Firewire, USB2, onboard
> sound,
> > > video, etc,etc.. But no parallel or serial ports !
> > > The only saving grace was the three PCI slots.
> > >
> > > If this is indeed the future of motherboards, then alternatives must be
> found
> > > soon for the IO we need for machine control.
> > >
> > > Regards, Paul.
> > >
> > >
> > > On Thursday 23 May 2002 7:09 am, John Sheahan wrote:
> > > > ISA is going away whether we like it or not.
> >
> >
>