Re: 68008 co-processor board complete working design available ...

[Jim Gilbert <brokerjim@gmail.com>]

On Dec 13, 9:46 am, Jim Gilbert <broker...@gmail.com> wrote:
> On Dec 3, 8:37 pm, Jim Gilbert <broker...@gmail.com> wrote:
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> > On Nov 25, 2:47 pm, Patrick Schaefer <pa.schae...@web.de> wrote:
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> > > Am 24.11.2010 21:53 schrieb Jim Gilbert:
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> > > > Newly posted information:
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> > > > (...)
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> > > Thank you very much! It would be great if you could provide binary
> > > versions of the sotware as well. I.e. a hex or bin file for the EPROM,
> > > and a dsk or shk with the Prodos part.
>
> > > Best regards
> > > Patrick
>
> > I am working on this...
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> > The binary is on Apple ][ 5.25" floppies. I no longer have an Apple ]
> > [. I do not have hardcopy source for the print spooler but I swear I
> > wrote one.
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> > I can recreate the softcopy of the Applesoft monitor and the DOS3.3
> > ram disk and the EPROM Monitor by OCRing the listings I have, I think.
>
> > Cheers.
> > Jim Gilbert
>
> After some extensive review of the design I have concluded that this
> could easily be upgraded to 512K of memory (ironically going from
> matching the original Mac to the "Fat Mac" in RAM).  There is room for
> the 1-pin longer sockets on the layout if the decoupling capacitors
> for the 4 memory chips are relocated to beside the chips instead of
> inline with them.  And you CAN still buy 256x8 FPM 5V DRAMs.
>
> The EPROM could be fairly easily upgraded to EEPROM.
>
> And an LED or two for RESET and HALT would be nice.
>
> I have seriously considered putting together a little breadboard
> driven by a spare ATX supply that would connect to power, a power
> button, the 50-pin backplane connector and a PC parallel port. Careful
> review of the 68008 board and a whole lot of parallel port
> documentation reveals that given power, the 68008 board would run with
> a PC parallel port interfacing to the backplane connector.  A QBASIC,
> or C, program driving the parallel port would replace the Applesoft
> DBG68 debugger.
> In a moment of weakness I ordered a cable with the 50-pin card edge
> connector.  The next step would be getting a little breadboard and
> some jumpers.  I can hear
> the cry "She lives!" from that old Peter Sellers movie already...
>
> So I may bring the board back to live without an Apple ][ just for
> fun.
> Of course I could buy another Apple ][.
>
> The easiest way to rescue the softcopy of the programs on the Apple ]
> [ floppies I have would be to mail them off to a trusty volunteer with
> a real Apple ][ and working 5.25" drive. They could be liberated from
> the medium and turned into disk images that are easier to save and
> toss around the Internet that way.
>
> Or more intriguingly, since I am out of space on the 68008 board I
> could use an Arduino, Beagleboard, Netburner, or PIC-breadboard for
> the host interface. This would allow me to easily add IDE/CF disk,
> Ethernet, Wifi or USB access to the 68008 via the host interface.  I
> might end up programming the host interface more than the 68008.
>
> And, other than the thrill of retro-hacking, what would you have?   An
> 8-bit 68008 with 512K RAM, a bi-directional 512x8 path to the host,
> and a serial port.
> Too small for uclinux. OK for SK*DOS, the USCD P-system*, or someone's
> real time system. OK for Contiki. No display capability except via the
> serial port to a terminal emulator.
>
> Of course a host interface with an ARM, x86 or Coldfire processor
> would already have Linux available on it.
>
> Intel, AMD, Microsoft, and all the Linux guys have buried us under GB
> of RAM, GHz of processor, and awesome high-res color displays.
>
> If I want to enjoy 68000 assembly language programming then the
> smartest thing to do is to do it on my Windows box via an emulator.
> This would be rather sterile.
>
> If I were to do the board again today I would use the free Coldfire V1
> FPGA core, do the bulk of the logic in the FPGA or CPLD, do it in
> 3.3v, use modern RAM, and allow for standalone or Apple ][ versions.
>
> Retro-ramblings, eh?
>
> Jim Gilbert
>
> *Regarding the UCSD P-system I once ported the II.0 P-system entirely
> to 8086 running on my Cromemco System III using a Seattle Computer
> Products S-100 8086 board, SCP-DOS 0.9 (the great-grandfather of all
> MS-DOS's, and Tim Patterson's monitor). I compared the performance of
> the UCSD system compiling the compiler using Z80 at 4 MHz, 8086 at
> 8MHz with 8 bit memory, 8086 at 8MHz with 16 bit memory, etc.  I had
> lots of experience with the P-System compiler because I had ported,
> extended, and maintained it for the Basic Four "Newport" 32-bit stack
> machines. I gave away, threw away all my P-system stuff when I moved
> from California to the East Coast in 1989.

I have now posted a board port addresses cheat sheet as well as .TXT
file version of completely revamped, commented, improved DBG68
Applesoft debugger.

The next softcopy to be posted will be the 68K monitor sources.

I intend to run this card again, either on a fixture connected to a PC
parallel port, or in a real Apple ][.

I am in considerable admiration of the great work done by Alex Freed
and others with their many excellent FPGA and/or CPLD projects.

Merry Christmas!