[Coco] atari USB device

[John R. Hogerhuis]

On Wed, 2004-11-17 at 19:49, Roger Taylor wrote:

> The hardest part of this project won't be the hardware.  The software 
> drivers will be the key to whether this can be done or not.

I don't think there's any possibility that it can't be done, however
ease-of-use and how many/what kind of devices will work will depend on
how it is done.

>   As much "BIOS" 
> software as possible needs to be put on a ROM in the cartridge so that both 
> Disk BASIC and OS-9 can have some consistency.  Besides, Disk BASIC has no 
> room for all this overhead code as patches.
> 

I agree that a cartridge is the way to go.

For BASIC ROM users, I would anticipate just assembly code libraries
linked into custom applications at first.

For OS-9 everything is simpler since we just have device drivers.

Sharing of code between programs running under BASIC and OS-9 will be by
sharing library code, even if only in source form.

Cramming the drivers into a custom BASIC ROM could happen as a separate
exercise once there's a proof of concept with monolithic applications,
or with device drivers under OS-9.

There's plenty of memory in the Coco 3 for drivers, although there isn't
in the ROM. So I would tend to just load them, or figure out a way to
bootstrap the drivers from a USB device if we ever get some form of USB
storage working.

Worst case (long term), if USB Storage can't be made to work, you could
make a combo USB Host controller + flash chip where the flash contains
position-independent firmware for accessing different USB devices which
could be loaded at will.

-- John.