[Coco] Re: atari USB device
farna at att.net
farna at att.net
Tue Nov 23 06:55:06 EST 2004
I'd like to see the USB device as a replacement for the disk controller, even if it was limited to that. The only problem I can see is that only 3.5" 1.44M floppy drives are available USB ready. There are USB cases for 5.25" devices, but all are for IDE or SATA devices. So a USB conversion interface would have to be made for 5.25" drives for backwards compatibility. Okay, maybe replacing the disk controller entirely isn't a good idea! But replacing the IDE controller is. It would make things much simpler! I know attaching a USB keyboard sounds great, but that might be a bit difficult to interface and wouldn't have as much appeal as disk and optical drives, especially if the type of drive didn't matter.
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-------------- Original message ----------------------
> Message: 2
> Date: Mon, 22 Nov 2004 09:42:27 +1100
> From: Mark McDougall <msmcdoug at optushome.com.au>
> Subject: Re: [Coco] Re: atari USB device
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Message-ID: <41A119D3.0 at optushome.com.au>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> Torsten Dittel wrote:
> > I had a quick view on the data sheet of that chip and it looks like it
> > only has 240 usable (from 256) bytes of data buffer. Not enough to hold
> > a disk sector. This will make the CoCo slow for other tasks than USB
> > access. AFAIR people started to build "No Halt" controllers with sector
> > buffered Disk I/O 20 years ago for that reason.
> USB data packets (at least v1.x) are only 64 bytes in length. So I'm not
> sure what the 240 bytes refers to in your post. With the USB protocol
> handling the handshaking the CoCo is left to emptying the 64-byte packets as
> fast (or as slow) as it likes. I really don't see an issue here...
> As James has re-iterated, we should be worried about 'crawling' first. The
> idea is not to be able to hook up 10,000RPM raid arrays and broadcast
> quality video digitisers. A USB interface merely opens up possibilities of
> interfacing modern devices (keyboard, mice, flash disks) purely for the
> 'because we can' factor and also for convenience.
> As much as we love our CoCos and insist that we can still be productive on
> them, the fact is that we're talking about a 2MHz 8-bit CPU - the embedded
> 8051 core in the Cypress EZ-USB slave chip itself runs at 12 MIPS!!! One may
> argue that what we're trying to do is quite silly and perhaps futile - but
> damn it's FUN!!!
> | Mark McDougall | "Electrical Engineers do it
> | <http://members.optushome.com.au/msmcdoug> | with less resistance!"
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