Re: Need card Identified, please.

[Brian A. Davis <badavis@nbnet.nb.ca>]

On Fri, 01 Apr 2005 08:28:35 +0200, Raymond Wiker
<Raymond.Wiker@fast.no> wrote:

>  Brian A. Davis <badavis@nbnet.nb.ca> writes:
>  
>  > I'm in the process of making scans of my A2 expansion card collection
>  > for a Web site I am creating. After that, I plan on trying to get my
>  > DTACK Grande 68000 co-processor board functioning (unless I get
>  > distracted by another A2 project).
>  
>          DTACK Grounded, possibly? I think there was both a 68000
>  enthusiast magazine and one or more 68000 boards of that name.
>  
>          The name, by the way, implies a configuration running
>  flat-out, with no wait states.

Hi Raymond;

"Grande" is correct. The DTACK Grande was the folow-up 68000 board
produced in 1983 (two years after the DTACK Grounded).

Here is a description of the Grande from the July 1983 issue of DTACK
Grounded Journal:

 THE DTACK GRANDE:

Above is a photograph of the prototype for the DRAM version of our
Apple compatible 68000 board. We have modestly named it the DTACK
Grande because it has a Grand(e) amount of memory: a megabyte! That's
called a full gallon here in California. (You can buy one with only
128K if you like.) This one has a 25MHz Xtal oscillator which we
divide by two to generate the 12.5MHz clock for the 68000. DTACK is
not grounded; there is one wait state. Refresh is performed in
software, with a hardware assist so that the overhead is exactly the
same for a megabyte as for 128K (4%). Thus the effective speed of this
board is equivalent to 10MHz with no wait states.

Which makes our one megabyte 68000 exactly twice as fast as another
one megabyte 68000 system that you Apple types may have heard of. The
other one doesn't work with Apple II's, of course. Ours does.

Because the refresh is interrupt-driven, this board is inherently
capable of multi-tasking so all you print spooler and type-ahead
buffer fans should love this board. We think it will make a dandy
RAMDISK. Oh, yes: it has a big, fast 68000 microprocessor (we almost
forgot while we were admiring all that memory!). 

================================

Brian