brianw@microsoft.UUCP (Brian Willoughby) (09/23/89)
I've been interested for some time in getting a simple DSP board up and
running in my Apple II Plus. Please don't laugh, I would basically be
using the Apple as a source of power and a cheap interface to a SCSI hard
disk. Since the 56000 host interface is 8 bits anyway, this seems like
a feasable project. Anyone have any experience with designing for the
56000 from the ground up?
I realize that assembling programs would be difficult without a
cross-compiler that would run on the Apple itself. I do have a full C
compiler which claims System 5 library compatibility. Does anyone know
of a simple 56000 cross-assembler, perhaps from Motorola?
Thanks for any help, ideas or suggestions,
Brian Willoughby
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Bitnet brianw@microsoft.UUCPmhorne@ka7axd.wv.tek.com (Michael T. Horne) (09/25/89)
In a recent article by brianw@microsoft.UUCP (Brian Willoughby): >I've been interested for some time in getting a simple DSP board up and >running in my Apple II Plus. Please don't laugh, I would basically be >using the Apple as a source of power and a cheap interface to a SCSI hard >disk. Since the 56000 host interface is 8 bits anyway, this seems like >a feasable project. Anyone have any experience with designing for the >56000 from the ground up? In my spare time I've designed a 56K based system that resides on a board for the PC/AT family. Layout/design for the chip is fairly trivial, so long as you are conservative in calculating external I/O and RAM/ROM access times (i.e. don't skimp). Fast static RAMs (such as the 16KX4 and 64KX4 parts) are relatively inexpensive, and their prices are dropping rapidly. My first proto was wire-wrapped, and I suggest that you take great care in layout if this is the method you wish to use. Use bypass caps liberally. >I realize that assembling programs would be difficult without a >cross-compiler that would run on the Apple itself. I do have a full C >compiler which claims System 5 library compatibility. Does anyone know >of a simple 56000 cross-assembler, perhaps from Motorola? One of the advantages in using the PC (or the Mac II, for that matter) is the relatively cheap assembler/simulator available from Moto. The C compiler, though far from bug-free, provides a very useful algorithm prototyping enviroment, and is also available from Moto. After designing the structure of the program in C, you can hand optimize (through in-line assembly), as well as write time-critical sections in assembly. As far as using the Apple II for this purpose, I can't say that I would really recommend it unless you can find a PD assembler. Writing an assembler for the chip is non-trivial, since the 56K is more of a microcode engine than a `regular' microprocessor (this is a positive attribute in my opinion, however one must accept the differences). I hope you can find something, but I wouldn't count on it (let me know if you do). Good luck with your project! Mike Tektronix, Inc. mhorne@ka7axd.wv.tek.com Michael T. Horne VSG/ITD, Tektronix, Inc. mhorne@ka7axd.wv.tek.com (503) 685-2077