[Coco] [COCO] Raspberry PI and CoCo Cart

Sat Oct 6 13:05:56 EDT 2012

These chips are rather expensive, and hard to get. Got me some for a
digital analyzer, which i still have to assembly. But if you play your
cards right in designing your idea, then I think it would be possible to
use the pi to store data (files) from DW into fifo, and then let the coco
use the fifo as read only ram ( use it actually as a Rom, and execute the
program from it. And being able to extend the fifo as long you want, you
have yourself a very fast medium, although it would be volatile. Would be
faster then read from any other flash or eeprom, I think.) Nice Idea I
would say.

Hope we get those electronic nerds exited ... LOL

cba

On Fri, Oct 5, 2012 at 11:31 PM, David Ladd <drencor at gamepixel.net> wrote:

> Here are one of the chips I was looking at.
> http://www.jameco.com/Jameco/Products/ProdDS/392446.pdf
>
> It has both a in and out clock so shouldn't be a problem timing data
> between Pi and CoCo.  Just need the cart with two chips that are like
> this and should be able to put together something that will interface
> the two together.
>
> I am still going through the chip list.  I will post when I find
> something that is a bit better.
>
> On Fri, Oct 5, 2012 at 7:48 PM, Aaron Wolfe <aawolfe at gmail.com> wrote:
> > On Fri, Oct 5, 2012 at 7:54 PM, David Ladd <drencor at gamepixel.net>
> wrote:
> >> Well my idea is is just addressing two FIFI buffer's at the Boisy
> >> Interface/Becker ports and then maybe modify the Drivewire 4 server to
> >> talk via parallel rather than serial using the Raspberry Pi's
> >> interface.  I need to find a parallel FIFO chips that can do this.  I
> >> figured a parallel interface would be a bit faster than serial plus
> >> two FIFO chips would provide at least a good buffer to allow the CoCo
> >> to catch up under OS-9 if other processes are going on between
> >> packets.
> >>
> >> Though I don't have a Pi yet and I figured since you have a Pi and
> >> wrote DW4 server that could come up with the required hardware to
> >> combine the Pi into a cart to basically be the CoCo's version of the
> >> Boisy Interface/Becker port.
> >>
> >
> > Well.. I haven't the slightest clue about hardware but I have been
> > talking to those that do.
> > I've gotten the impression a FIFO/Boisy/Becker interface is very
> > possible for someone
> > with the knowledge to make things.  That would be cool, I just wonder
> > if we couldn't do
> > something a bit lower level and turn the Pi into a flexible I/O
> > controller rather than a
> > drivewire server on the end of a serial connection... there are some
> > pretty massively
> > nice things such a device could do.
> >
> >> The only thing I know right now is that anyone who still uses a J&M
> >> Controller with a built in parallel port would have to switch to
> >> another floppy controller since it uses the same address ports.
> >>
> >> I still need to do more research into the FIFO chips and if 8bit ones
> >> are made.
> >>
> >> I figured using the becker port would make things a bit easier since
> >> NitrOS-9 already has the DW driver for it.  The only thing that would
> >> need to be done is for someone who has rights to update the source
> >> code to the HDBDOS project could update the DW read and write files to
> >> include the becker port and then add to the make file to produce
> >> another HDBDOS image that includes a becker compile of HDBDOS.
> >>
> >
> > It's true that implementing the B/B interface means no additional
> software needs
> > to be written..  conversely it also means no additional functionality,
> > just much
> > better speed.  That's good, but I want to at least explore doing more.
>  It may
> > well end up that a fifo is the only practical way but I haven't given up
> yet.
> > If we had a way to communicate from coco to usb/ethernet/etc on the pi,
> > believe me I will write the software to use it.
> >
> >
> >> On Fri, Oct 5, 2012 at 6:24 PM, Aaron Wolfe <aawolfe at gmail.com> wrote:
> >>> I have been wanting/planning/trying to gather information on a "Pi in
> >>> a Pak" for some time now.
> >>>
> >>> Interfacing via a faster, less CPU intensive DriveWire connection is
> >>> interesting, and maybe that is the limit of what can be done.
> >>> However, I had hoped for something a bit different.  I've talked with
> >>> some experts (or at least they know a heck of
> >>> a lot more about it than I do) and gotten some ideas but maybe the
> >>> list has some too...
> >>>
> >>> It seems like the ideal (and maybe unobtainable) interface would be
> >>> one which can read and write directly to the
> >>> bus lines just like a regular ROM pak or drive controller.  Given this
> >>> ability, one could accurately simulate *any*
> >>> pak or peripheral (or several at a time?).  You could also create new
> >>> peripherals, such as interfaces to the various
> >>> I/O found on the Pi (USB, ethernet, audio/video, etc...).   Way better
> >>> than an embedded DW server imho.
> >>>
> >>> I don't know if its possible or practical, I just know that it would
> >>> be awesome.  From what I've gathered... it might be possible
> >>> but it's not a sure thing.  You have to dance pretty fast to play on
> >>> the bus.  The Pi does have an SPI interface capable of many
> >>> Mb/s throughput (one guy's testing says 16Mbps is a practical limit)
> >>> in addition to several GPIO pins.  John Kent showed me
> >>> a cheap I/O processing chip that was cheap, programmable, had SPI and
> >>> a whole bunch of latches, and could operate in the
> >>> multi Mhz range.  Can they be stuck together into something that can
> >>> participate on the coco bus?  I wouldn't even know how
> >>> to guess, but I'd surely like to find out.  Also interested in
> >>> alternate schemes that provide superior/more direct communication
> >>> than the DW style serial line.
> >>>
> >>> Can the Pi be turned into the ultimate virtual MPI?  $0.01 for your
> thoughts
> >>>
> >>>
> >>>
> >>>
> >>> On Fri, Oct 5, 2012 at 7:09 PM, David Ladd <drencor at gamepixel.net>
> wrote:
> >>>> One of the things I was thinking is with the cart side is having two
> >>>> FIFO chips to buffer data between the Raspberry Pi and the CoCo.
> >>>>
> >>>>
> >>>> On Sat, Sep 29, 2012 at 5:58 PM, Aaron Wolfe <aawolfe at gmail.com>
> wrote:
> >>>>> On Fri, Sep 28, 2012 at 10:42 AM, Brian <briang0671 at sbcglobal.net>
> wrote:
> >>>>>> On 09/28/2012 12:05 AM, David Ladd wrote:
> >>>>>>>
> >>>>>>> Here is a interesting idea I just had.
> >>>>>>>
> >>>>>>> What if we were to interface a Raspberry PI and have it connected
> to a
> >>>>>>> CoCo cart so you could take advantage of the Boisy Interface/Becker
> >>>>>>> port so that you could have faster access to drivewire 4 server?
> >>>>>>>
> >>>>>>
> >>>>>> What is the Boisy Interface/Becker port?
> >>>>>>
> >>>>>
> >>>>> This is a fifo buffer interface implemented initially in the
> CoCo3FPGA
> >>>>> project and since ported to some emulators.  It allows DW to operate
> >>>>> at very high speed/low cpu use compared to bitbanger on those
> >>>>> platforms.  OS9 modules to support the interface are in the NitrOS9
> >>>>> source.
> >>>>>
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