[Coco] Multipak redesign/replacement

embsys dev embsysdev at gmail.com
Tue Feb 24 22:44:19 EST 2015


Nice.  I wish I had a great grandpa like you to tell me stories like that
all the time.


On Tue, Feb 24, 2015 at 8:39 PM, Gene Heskett <gheskett at wdtv.com> wrote:

>
>
> On Tuesday 24 February 2015 21:03:57 RETRO Innovations wrote:
> > On 2/24/2015 8:11 AM, Gene Heskett wrote:
> > > Working from memory, no.  Because I hacked the decoding in the packs
> such
> > > that my normally loaded packs, an fdc, a tc^3 and a dual port rs232
> pack
> > > can all live together. And the wp-rs that is not now in the system
> since
> > > Boisy threw away my special drivers very early in his sysram wasting
> > > cutting up of drivers to make them one function drivers.  But he was
> > > running the show and my messages to him went into a black hole at the
> > > time.  The oem version of the wp-rs used 2 address in one 4 byte wide
> > > reservation and 2 addresses in the next one up, so that decoding and
> the
> > > driver got fixed in my own setup.
> > >
> > > So if the contents of the mpi are relatively fixed, any addressing
> > > clashes can be fixed in the pack itself.  But this of course works only
> > > for me and other hardware savvy folks, and is a dismal failure for
> > > someone who doesn't even know which end of a soldering iron gets hot,
> let
> > > alone follow the logic of a 74LS138. :(
> > >
> > > The ideal situation, but a non-starter, would be to put the address of
> > > the pack in ALL descriptors and decode on the mpi board to select which
> > > slot based entirely on the 4 byte wide i/o address in the descriptor.
> > > That of course is a non-starter because the /CS logic in the packs
> would
> > > have to be bypassed and thats still a non-starter for the hardware
> > > compromised user who can't fix it on his own kitchen table.  All of the
> > > current fdc's waste a $10 byte wide i/o space that with the full
> decoding
> > > could be limited to $08 bytes, freeing 1 more address slot of 4 bytes,
> > > And just that one additional space would go a hell of a long ways
> toward
> > > solving the I/O space problems the coco3's gime throws in our laps
> like a
> > > cup of McDonalds coffee.  Of coarse this doesn't fly if there is a real
> > > time clock. Mine had 2 but its been removed from the SC-II 4n1 for a
> > > while now. Running  a lot better on the tc^3 clock.
> >
> > Well, I'd sure like to get more information.  I have some ideas, but
> > need to understand the issue before suggesting one.
> >
> > Jim
>
> Ask away Jim. You can go to PM'ing me, but I would rather that anyone on
> the
> list who can understand what I'm saying in those areas where I do have
> decades long experience with, a chance to learn something for their own
> edification.  Hopefully I just did that with my Transmission lines 101
> message of ten minutes ago.
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Genes Web page <http://geneslinuxbox.net:6309/gene>
>
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>


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