[Coco] Drivewire client for OS9/68K

[Aaron Wolfe]

On Mon, Aug 30, 2010 at 8:59 PM, Joel Ewy <jcewy at swbell.net> wrote:
> On 08/29/2010 09:29 PM, Bob Devries wrote:
>>
>> Hi Joel,
>>
>> I'd guess that a DW client for OS9/68K would involve merging parts of the
>> serial driver such as SC68681 and a hard disk driver (I have source for 2 of
>> those, and the sc68681), and then add the special commands for DW.
>
> Is that the way it's done on the CoCo?  What part of the disk driver would
> need to be in there?  I need to look at the source.
>

DW on the CoCo/OS9 is implemented in two parts: One is an RBF driver,
the other is used by that driver to talk to the hardware.  Assuming
RBF works the same on OS9/68k, the RBF portion should be a fairly
straightforward port.  The hardware portion would be a bit different,
but it only implements a couple calls (send some bytes, read some
bytes).  Shouldn't be too hard to adapt.

> Also, regarding hardware flow control on the 68681 ports -- DW on the CoCo
> is done on the bitbanger port, so no hardware flow control there.  I'm
> guessing that interrupts are masked quite a bit of the time.  Maybe the MM/1
> could bit-bang with one of the parallel port lines -- it might even be
> faster than the UARTs...
>

This is true.  If you have parallel lines, might want to use them
instead.  In any case, flow control is not needed with DW.

>>
>> BTW, I need to hack the clock chip on my IO board; the battery in the
>> clock module is now dead. I have seen some info on how to connect an
>> external battery to one of these. I don't have a lot to lose if I try it.
>>
>
> I've got a rail or two of those Dallas clock chips, unused.  But the
> batteries in them are just as old as yours.  ISTR that those Dallas chips
> use a compatible pinout to that Motorola RTC that doesn't have a battery.  I
> wonder if you could pull the clock out of an old '286 or '386 PC
> motherboard, bend a couple pins out, and strap a battery on the back of
> it...
>
> JCE
>
>> ----- Original Message ----- From: "Joel Ewy" <jcewy at swbell.net>
>> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
>> Sent: Saturday, August 28, 2010 12:22 PM
>> Subject: Re: [Coco] Drivewire client for OS9/68K
>>
>>
>>> On 08/27/2010 07:56 PM, Bob Devries wrote:
>>>>
>>>> Hi all,
>>>>
>>>> what are the chances of a drivewire client being built for OS9/68000?
>>>> The (extended) MM/1 is well endowed with serial ports via the 68070, 68901
>>>> and 68681 chips. I'm sure they'd be capable of the speek necessary.
>>>>
>>>
>>> Bob, you and I may be the only two people on this list who still have
>>> working MM/1 systems (though I'd love to be proven wrong) and I need to put
>>> a 'new' hard drive in mine.  Fortunately I have a small supply of SCSI
>>> drives from old Macs.  I really need to figure out how to use a SCSI ZIP
>>> drive on the MM/1 though, so I have some reasonable way to back it up... But
>>> Drivewire would really help that situation as well.  I would love to have a
>>> DW client for the MM/1.
>>>
>>>> I notics that it is no longer possible to browse the source tree of
>>>> NitrOS9; else I'd have a go myself at trying to build a 68K version.
>>>>
>>>
>>> Time permitting, I'd be willing to help in the porting effort.  My
>>> experience in 68000 assembler is limited to a few exercises in a class about
>>> 20 years ago, and my C is only marginally better by most reasonable
>>> standards, but there's some motivation to learn.
>>>
>>> JCE
>>>
>>>> Regards, Bob Devries
>>>> Dalby, QLD, Australia
>>>>
>>>> --
>>>> Besides a mathematical inclination, an exceptionally good mastery of
>>>> one's native tongue is the most vital asset of a competent programmer.
>>>>
>>>> Edsger W.Dijkstra, 18 June 1975
>>>>
>>>>
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>>>
>>>
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