[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. 

Frank Swygert
Publisher, "American Independent 
Magazine" (AIM)
For all AMC enthusiasts
(free download available!)

 -------------- 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!!!
> Regards,
> -- 
> |              Mark McDougall                | "Electrical Engineers do it
> | <http://members.optushome.com.au/msmcdoug> |   with less resistance!"

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