[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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