Re: [CAD_CAM_EDM_DRO] PIC DRO Dreaming / how about $99 ?

> From: Doug Fortune <pentam@...>
>
> Your dream come true: 180Mhz/32MB/800x600 16 bit color LCD for $99.
> 16MB flash for programs (ide optional).
>
> http://www.linux-hacker.net/iopener/
>

That is a nifty little machine (a hackable internet appliance) and
I'm resisting the urge to get one as soon as Circuit City gets them
back in stock. However:

You bascially have a parallel port for I/O. Presumably it is an ECP
or EPP or whatever - but there would be no use for that in the
intended application so it would only be such if that were a feature
of the commodity chipset used. This might be enough for a DRO without
too much hacking, but DRO plus machine control would require some
serious multiplexing that might start to limit performance unless done
very carefully.

There is a modem on an internal riser card that could be removed to
possibly reveal something vaguely ISA-like but there again we are
talking about building a lot of custom hardware for a machine that may
not be available very long (apparently they are worth around $600 -
company may start to make the cheesy internet service where they
intend to make their money mandatory if a lot are being bought up by
people who just want a cheap machine).

For network connectivity, the simplest solution is a parallel port
adapter (supported by linux) which, come to think of it, implies a
modern bidirectional port. Of course this gets in the way of using
the port for DRO or control applications. There is a USB port, so
that should work with BSD now or linux when USB ethernet support
becomes stable.

A nify thing about them is that while you can add a laptop hard drive
and run linux - or presumably RTlinux, they nativley run QNX, which is
a commercial realtime unix. Apparently if you plug in a keyboard that
actaully has an escape key (theirs doesn't for this reason) you can
press a magic combination (esc-4) and get a root shell - kill the
process that dials their ISP and explore the machine. I predict
someone will figure out how to hack the dialer to connect to typical
ppp type ISP instead. If you could then download a DRO program that
would run under QNX you could avoid opening the box and the expense of
adding a harddrive to simply get DRO functionality.

Chris

--
Christopher C. Stratton, stratton@...
Instrument Maker, Horn Player & Engineer
30 Griswold Street, Cambridge, MA 02138
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