[Coco] (no subject)

[Gene Heskett]

On Sunday 07 December 2003 12:34, David Hazelton wrote:
>peak at mail.polarcomm.com wrote:
>> Why not just build a bi-directional parallel port into your
>> COCO?
>
>What for?,  I was always curious what use the Bi-directional
> parallel port would honestly be used for.  The MM/1B has one, but
> no one that I know has actually used it for more than a simple
> printer port, let alone a Coco.
>
>I guess, if KAQ9 can do SLIP, with the Bi-directional parallel port,
> it could be made to do PLIP and maybe do a higher connection rate
> to a Windows based direct connect. (I guess Linux too).  I know I
> used to connect my MM/1B to my Windows machine using Slip, So Plip
> should work. And should work on the CoCo too if it had a real
> Bi-directional parallel port and Bi-directional drivers.

Working from mental history here, something Mark M. has designed in 
recent history may also qualify, but the only par port for the coco 
that was bi-drectional was AFAIK the one on the J&M-CP controllers.  
Unforch, its not latched in either direction so to use it fully will 
require some sort of a latching buffer on it to synchronize the data 
transfers.  That should be built fairly close in as cable ringing 
would probably fubar things.  One of the reasons I never got around 
to doing it but should have.  The disto port did work, with the same 
printers so the choice was pretty clear-cut to me, being basicly 
lazy. :(

I could occasionally use it to drive a printer, but as later parport 
printers got more and better filtering courtesy the fcc edicts, the 
parports on the printers got too slow to properly register the data 
from the coco running a 1.79mhz as it was only valid during the E 
clock generated strobe pulse on the port.  Old, slower coco1's could 
get thru, but not the faster coco3's.

Any disto parport is write only AFAIK.

>And do Zip drives use SCSI commands or ATAPI when connected thru the
>Bi-directional parallel port of a PC.  Which as far as I know we do
> not have ATAPI support on the Coco and the MM/1B.  (But I could be
> wrong.)

Zip drives, even the parport models, do use scsi command packets 
AFAIK.  Their addressing is limited though, to only 4-6 on the real 
scsi buss.  Later ones were apparently hard coded to 6.

>~David Hazelton

-- 
Cheers, Gene
AMD K6-III at 500mhz 320M
Athlon1600XP at 1400mhz  512M
99.22% setiathome rank, not too shabby for a WV hillbilly
Yahoo.com attornies please note, additions to this message
by Gene Heskett are:
Copyright 2003 by Maurice Eugene Heskett, all rights reserved.