Apple II for intro to microprocessors

From: Richard Erlacher <edick_at_idcomm.com>
Date: Mon Jul 16 19:48:07 2001

There's no doubt about it, Mike, the Apple was quite useful for a lot of things.
I simply pointed out that with a different device, costing about $90 rather than
the considerably more that an Apple][ cost back in '79, you could do much of the
same stuff, unfettered by the restrictions that the Apple hardware put on you.

Now, I don't remember what an Apple proto card cost back then (I still have one
of those I bought back in '80) but those were bought to build a HDC for the
Apple.

I find the 6801L1 quite a bit better for dealing with the basics of handling
microprocessor related issues, since they don't have the video timing logic
defining the clock rate. That's not because the Apple is bad, but because it's
easier to deal with the naked processor than the entire system. Having the
ability to define a clock rate based on your application needs rather than those
of the video timing makes it possible to save on costs and effort. Many
applications, particularly those of low volume, make it cheaper, overall, simply
to build an Apple, or, nowadays, a PC into the solution.

Dick

----- Original Message -----
From: "Mike Ford" <mikeford_at_socal.rr.com>
To: <classiccmp_at_classiccmp.org>
Sent: Monday, July 16, 2001 2:09 PM
Subject: Re: Apple II for intro to microprocessors


> >While there are a lot of processor-application-related things you are
> >prevented
> >from, or at least, restricted in, accomplishing because of the restrictions
> >placed on the hardware by the design of the platform, there certainly isn't
> >anything you can't do from a computing standpoint. However, that was my
> >point.
> >The things that define a microprocessor-based system are fixed in the Apple,
> >mostly by its video timing restrictions, but also by its memory map and
> >the way
> >in which I/O is managed.
>
> ONLY if you restrict yourself entirely to the Apple II hardware. Anything I
> couldn't directly do internally on the Apple I could put on a protocard and
> just use the Apple as a convient disc drive and display.
>
> >There's no question that one had to read quite a bit. However, most of the
> >materials written about microprocessors were really dedicated to
> >microcomputing
> >rather than the application of microprocessors. Device manufacturers
> >weren't of
> >much help either because they wanted you to buy their particular development
> >systems, with their limitations, and those didn't often help very much.
>
> What I was refering to in books were timing diagrams, not how to write a
> new version of CheckBook. My work in embedded control was as much about
> gate delays as gosubs. I never ran into the "restrictions" and found the
> Apple II a very convient platform to develope from. A 6520 on a cheap Apple
> II I/O card doesn't behave very differently from the same chip on a
> protoboard as part of a 6502 based controller. Many many apples crossed my
> bench and sat on my desk with a loom of wires trailing out the back to
> simulate some process before the "real" boards were ready.
>
>
>
Received on Mon Jul 16 2001 - 19:48:07 BST