[sebhc] USB for the H8?

[Patrick]

> > Has anyone given any given any thought to building a simple USB
> adapter for
> > the H8?  It seems there are lots of inexpensive solutions for
> adding USB.
> > Add an inexpensive thumb drive and write a device driver and you're in
> > business. I'd be interested in hearing from anyone who's tried
> it given this
> > some thought.
> >
>
> What about building an SVD with a USB socket on it?  Cypress makes some
> really cool USB controller uP chips.
>
> g.

Here comes the heretic in the group. :-)

Guys, I don't want to be a nay-sayer, but there's a lot more to supporting
USB than just providing the port, even with a uP that integrates it.  If the
goal is to create a simplistic device to operate USB-based random access
storage devices, even the differences between storage devices can make the
driver large and potentially too tempermental to be of archival value.  The
fact that any random device you choose to buy can just be plugged in and
works at some level is the product of man-decades of labor in driver
development and QA (let alone the hardware), some of those drivers having
shipped with the OS, but some requiring separate installation on first use
of the device.  Go find the DLLs on Windows for these drivers.  Most are
larger than the entire memory of our target machines.  On my Win2K system,
the basic USB driver is 39K, add 30K for the basic USB disk driver.  Too
much.

So then what?  You could create a simple interface between the uP and the
8/89 and leave all the smarts there, which reduces the driver load on the
small-memory system, but you still have gobs of labor on the uP side, and
unless the device is Flash-updatable and someone supports it, it can't
survive.  In ten years, that uP itself will be old news, not supported, and
possibly not even available (and not collectible, so good luck finding a
replacement if you need it, assuming you can Flash it yourself).  And for
long-term storage, I don't think USB drives (hard or flash) are particularly
well built compared to their "bare metal" kin.  They're intended to be the
"Bic Pen" of storage media.

For me, I'd play it conservative and choose an IDE- or SCSI-based design.
They are simple interfaces that are near in architecture both to the
hardware of our target machine and to the software environment on which they
will run.  They can implemented using anything from TTL to simple PIOs to
programmable gate arrays.  Both of these interfaces have been an enduring
standard of storage connection for two decades or more.  Even Serial ATA is
simpler than USB.  The drivers required in these solutions are minimal, and
similar approaches for other systems like Howard Harte's new/modern
Super-I/O card for S-100 machines demonstrate both the relative simplicity
and tremendous value (it supports floppies and IDE, and by extension
CompactFlash).

To quote a famous movie: "The more you complicate the plumbing, the easier
it is to stop up the drain."  Back in the day, everyone wanted to KISS it.
That's the spirit to be kept alive.

Just my 2p.
Patrick

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