Apple II for intro to microprocessors

From: Mike Ford <mikeford_at_socal.rr.com>
Date: Mon Jul 16 15:09:46 2001

>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 - 15:09:46 BST