home .. forth .. colorforth mail list archive ..

[ColorForth] "serial" USB (was: Re: Why I'm Here)


Thank you for your response, Mr. Sanford.

Sorry, I didn't communicate properly (bad habit of mine). 

I meant if it was possible to use a PC's existing USB ports in a "limited
fashion" by ditching most of the "standard" (e.g. multiple devices, etc.) around
USB and most of its "supporting software" so it would act [and perform] much
like a high speed serial port. Frankly, I am not pleased with the delays
encountered with full USB implementations (despite its higher overall
throughput) for real-time applications, and I have several items in mind I'd
like to connect to my computer without this delay if all possible.

I am also hoping that in the process of "limiting" the USB implementation to
roughly that of a high speed serial port, that as you had also addressed for me
indirectly, the modifications required of my existing "serial" based equipment
would be very minimal.

Any thoughts on this?

On the subject of the 25x, which you addressed...I, too, could fully appreciate
full USB implementation on the 25x (with no real qualms at this point). Assuming
of course, that this is where others are interested as well.

Thanks for your time.

Best regards,
-- Art

> Being indepentant is great if you can get everything you want, but
> if you want to print your code, attach a keyboard, attach a mouse
> etc .... USB is at least a single port that allows one to get access to
> a wide variety of standard peripherals that should support almost
> everyones interest.  Serial or parallel ports are much easier to design
> 
> but the number of supported devices will be very limited and as the 
> no-legacy PC movement continues the old style interfaces will go away
> and you won't be able to find them, this day isn't that far off.  The 
> no-legacy movement of a couple of years ago failed but as now almost
> everything is available with USB now, the old interfaces of serial,
> parallel, Floppy and ISA slots will disappear.  
> 
> USB isn't an easy standard to get working and this will be a major
> downside, USB slave devices aren't too bad to program but masters 
> require a significant effort to support a wide range of devices. 
> Luckily Linux has been working on this for the past couple of years and
> is fairly stable.  This is a pretty big chuck of code that would need
> to be ported to Forth and goes against many of the recent comments of
> I'll build a system to meet my needs and my needs alone.  I understand
> this idea, as you often end up will significant overhead (baggage) that
> isn't needed and contributes to system bloat and speed (lack of), but
> for a single interface that can get to printers, modems, storage
> devices(HDD,FDD, Flash cards), cameras, keyboards, MP3 players, the
> effort seems worth while and those who want to run bare bones can.  
> 
> Another thread mentioned dropping TCP/IP support again I understand the
> argument that this is a lot of work but again having this one protocol
> gives access to so many other devices that it makes sense to put effort
> into this one area.  One possible solution is to have a 10/100baseT
> connection that can make requests of a PC/Mac/workstation and have the
> drivers available on that machine using Windows/Linux/Unix/MacOS, i.e.
> you want to write to a floppy send a ethernet/TCP/IP message and have a
> small peice of code that receives this data on the PC that writes the
> data to the floppy, no drivers required, but it does limit the overall
> usage of the x25 to being a slave to the PC/Mac/Workstation when access
> to a peripheral is required.  
> 
> If you are nonstandard you have to create everything yourself and the 
> effort going into Linux should be a sign that creating device drivers
> is a long and hard process.  If you only have intererst in a narrowly
> scoped embedded system maybe you can get away with that but do not
> expect help from others as they will be working on thier narrowly
> scoped system that isn't compatible with yours.  Forth history seems to
> be littered with many incompatable systems with limited or no
> documenation, if there isn't some form of standard platform the history
> will continue.  Computers have gone from multi-million dollar room
> sized machines, to cheap small machines because they are generally
> available and useful to multiple people, high volume => low cost.  The
> x25 chip is only $2 if the volume is high, if there isn't support for a
> wide variety of apps/devices the volume will be low, the cost will be
> high and the concept fails.
> 
> The first thing that I learned as an engineer was don't invent when you
> can buy, its always cheaper in the long run, so if interfaces or
> protocols exist use them.  Interfaces or protocols that have wide
> support are that much worth while, (Metcalf's Law: the value of the
> network goes up with the cube of the number of nodes).  TCP/IP and USB
> are perfect examples of a little concetrated effort paying off hugely. 
> As stated above you can either take a stand-alone slant and use USB or
> TCP/IP/ethernet for a network connectivity, but it seems to me that at
> least one of the two should be considered a requirement.   
> 
> 
> --- "Arthur W. Green" <goshawk@xxxxxxx> wrote:
> > 
> > > 
> > > Will I abandon the PC when I get a 25x with USB peripherals?
> > > 
> > Along these lines...
> > 
> > Can anyone tell me if there is any particular reason why we couldn't
> > just ditch
> > most of the USB standard and just use a single port on a bus (if
> > multiple ports
> > exist per bus) as a high-speed serial port and forget all about
> > device sharing
> > and the like on a typical PC?
> > 
> > I figured at least for real-time applications, this would certainly
> > cut down on
> > granularity and the like...
> > 
> > If not, is there any particular reason why this isn't a good idea for
> > USB
> > capability on the 25x?
> > 
> > Best regards,
> > -- Art
> > 
> > PS: I thought I sent this before, but I didn't see it in my inbox
> > this morning.
> > Sorry if this is a repeat.
> > ------------------------
> > 
> > To Unsubscribe from this list, send mail to
> > Mdaemon@xxxxxxxxxxxxxxxxxx with:
> > unsubscribe ColorForth
> > as the first and only line within the message body
> > Problems   -   List-Admin@xxxxxxxxxxxxxxxxxx
> > Main ColorForth site   -   http://www.colorforth.com
> > 
> 
> __________________________________________________
> Do You Yahoo!?
> Buy the perfect holiday gifts at Yahoo! Shopping.
> http://shopping.yahoo.com
> ------------------------
> 
> To Unsubscribe from this list, send mail to Mdaemon@xxxxxxxxxxxxxxxxxx with:
> unsubscribe ColorForth
> as the first and only line within the message body
> Problems   -   List-Admin@xxxxxxxxxxxxxxxxxx
> Main ColorForth site   -   http://www.colorforth.com
> 
------------------------

To Unsubscribe from this list, send mail to Mdaemon@xxxxxxxxxxxxxxxxxx with:
unsubscribe ColorForth
as the first and only line within the message body
Problems   -   List-Admin@xxxxxxxxxxxxxxxxxx
Main ColorForth site   -   http://www.colorforth.com