[Coco] Thought

[Mark Marlette]

At 9/24/2004 07:26 PM +1000, you wrote:

Mark,

The CoCo is faster than a floppy. We have done it with our hard drive 
interfaces. Faster than today's protocols, no way, 6x09 is the bandwidth 
barrier and more so the GIME in the CoCo.

I haven't looked at the nth degree of USB, but I view it as being not much 
different than implementing it like I'm doing on the Ethernet side.....An 
embedded processor that takes care of EVERYTHING and just hands data to the 
8 bit uP. It is a purchased chip set solution, proven, it works well and is 
VERY impressive. I'm sure there are USB solutions as well. I just haven't 
taken it that far. Nor do I plan to with the project I have going on currently.

All fun here, after 20 years this machine can still teach you something. ;)

Regards,

Mark
Cloud-9
http://www.cloud9tech.com




>mmarlett at isd.net wrote:
>
>>If your device was to interface to the floppy controller of a coco then I
>>  would see no speed improvemnts over the current floppy due to the timing
>>  loops that are in the drivers that are in RSDOS and NitrOS-9.
>
>I'm not sure how the CoCo drive works - I'm guessing from your comments it 
>doesn't interrupt the 6809 when data is ready?!? IIRC the TRS-80 Model 3 
>interrupts the Z80 when a read sector command is ready to pump data back 
>to the CPU and (I'm not 100% sure of this bit) when a new byte is ready. 
>At least with that setup you could (theoretically) eliminate the seek and 
>step times from the equation and pump back data as fast as the Z80 could 
>read it in.
>
>>Making a new interface would allow you to go as fast as the coco can
>>which is faster than a floppy. Then you would have to write drivers.
>
>True. But in general are people doing things with their CoCo that are 
>I/O-bound anyway? I would've thought that they're not moving a *lot* of 
>data around, but rather are being restricted by the 2MHz 6809 CPU??? In 
>any case, a CoCo doing PIO isn't going to be able to pump much data 
>to/from a disk running at 2MHz, certainly nowhere near 480Mpbs of USB 2.0. 
>It'd be closer to 800kbps if you assume ~20 clocks/IO...
>
>>I would love to see USB devices on the CoCo.
>
>It ain't gonna happen, IMHO. Ever looked at the linux source for the mobo 
>USB controllers? I have, and you won't be doing it with a 2MHz 6809...
>
>Regards,
>
>--
>|              Mark McDougall                | "Electrical Engineers do it
>| <http://members.optushome.com.au/msmcdoug> |   with less resistance!"