Re: DSP

[kpopple@imp.sim.es.com (Ken Poppleton)]

In article <2bmafc$d13@ionews.io.org>, taob@ionews.io.org (Brian Tao) writes:
> In article <1993Nov6.230432.18133@monu6.cc.monash.edu.au>, Donny writes...
> > 
> > So whose interested in building a DSP card for the gs?   I am, and a
> > mate of mine who is an electronics wiz, a gs programmer and user is.
> 
>     Is Ken Poppleton still working on his?  I'd love to plug in a cheap
> DSP card (~$150) that can do all the things DSP's love to do.  ;-)

YES, I am continuing to work on the DSP card.  It has been slow with many
delays.  Sorry for not keeping everyone informed of the progress...

Here is a status report/quick board description...


The DSP board will be a modular system of several seperate boards...

First I have decided to Isolate the DSP processor board from the
Interface development.  This has allowed me to concentrate on getting
the DSP processor board design completed.  It also allows myself or
other to create improved versions of the interface board without the
need to replace the expensive part, the DSP processor and memory.  It
will also allow the development of other host interfaces for other
computers thus hopefully increasing the production volume and thereby
decreasing the price of the DSP processor boards to everyone.  Also
as the DSP processor board will most likely be a multilayer board, and
interface baords can be two layer, different versions of the interface
board will not be as expensive to create, they can even be
wire-wrapped as is my first proto interface board.

So if there is anyone that would really like to work on an interface
board to take full advantage of the Apple II using DMA and interupts
let me know.  Espically someone who would like to do a DMA version for
the IIgs (as I only have a IIe!).


The serial ports are on a seperate connector which creates a daughter
board over the interface board.  This is for any add on boards using
the high speed serial ports.  I expect to see simple RS232/422 serial
boards, audio D/A, A/D boards and other IO functions to be put on the
serial daughter cards.



The full processor bus will be on the third connector.  This will have
to be a fine pitch connector as it must carry over 60 connections in
less than 2.5 inches.  This is so a daugher card can be added over the
DSP processor board, which needs to use the processor bus.  Any memory
mapped devices or additional memory would be put on a card connected
to this connector.


The DSP processor board will have a Motorola DSP56002 40Mhz processor
with a PLCC socket for a 27c256 Eprom or 28c256 EEprom, and a 8kx24bit
zero wait state static ram, along with all the support elements.  The
board can be used with a host system through the interface board
connected to the host port of the DSP56002 or as a standalone
processor for embedded applications.

I have limited the board to the minimum to keep the price down and so
it would fit into the space required for an AppleII.


STATUS:  Design is complete, wireing up a final proto (hand wireing).
and beginning to work on transfering the design into a cad system for
board layout.


For those who want to use the DSP as a fast math coprocessor, it is
very good for integer math but is about 8 times slower than the 68882
floating point coprocessors at doing floating point math.  Using a DSP
requires the developer to know the range and resolution of numbers and
design the system accordingly.  By doing carefull design many systems
run faster on an integer DSP than a floating point coprocessor because
the design time was applied to understanding and using the integer
math over using floating point math.  But if floating point is
required then a floating point coprocessor is the best tool to use.



Contact me by Email for specific questions or post to the net and I
will try to reply (I do not always get the time to read the net news).


I am glad to see the interest is still there.
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Ken Poppleton 
kpopple@imp.sim.es.com
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