Getting started with digital electronics in general

[eodell]

Hi all.

I have for years nursed an ambition to build a moderately sophisticated 6502-based homebrew computer on a par with the Apple IIe (though not compatible with it, per se). The ideal system for me would have at a minimum 256k of bank-switched RAM, a rudimentary operating system in ROM, a standard serial port, a connector for a standard PC keyboard, a video controller similar to that in the Apple II, and a controller for a standard 1.44MB floppy. Provision for add-on slots in case I get really ambitious, like say an IDE controller, would be nice.

Now here's the part that will probably make most of you laugh. While I am a professional programmer today and was, once upon a time, reasonably proficient with 6502 assembly language, I know jack diddly about electronics. Oh sure, I know electricity flows in circuits and I can tell you what a resistor and a capacitor are, but if you sat me down with a box of parts, I'd be hard pressed to do much more than connect a D cell to a flashlight bulb with a couple of wires. I know enough, basically, to be properly daunted by my ignorance.

So my question is: what books/software/kits should I invest in to follow the straightest possible path to my goal? I know this borders on the ridiculous, but I've got to do it, and I might possibly have enough spare time over the next several years to make a serious go at it.

Thanks,
Eric

[John West]

Horowitz and Hill "The Art of Electronics" teaches everything (and more) that most people need to know.

Also valuable is obtaining the schematics for similar machines (bound to be a few on 6502.org) and staring at them, TTL databook and processor datasheet in hand, until you understand how they work.

Do they still print TTL databooks? All the datasheets will be on TI's web site anyway.

[8BIT]

Hello Eric,

I am 99% self-taught in digital electronics so it can be done. I started out by reading the hobby electronic magazines of the day (Popular Electronics). I also bought a few books that showed some simple circuits using logic gates and flip-flops. Eventually, I bought a single board computer and soldered it together and began learning machine language.

As far as putting together the hardware, most if not all of what you want to build has already been designed by others. Search the "homebuilt projects on the web" page on 6502.org. You'll find several basic computers along with a wide array of peripherals, including PC keyboard I/O and IDE interfaces.

Good luck!

Daryl
http://65c02.tripod.com/

[GARTHWILSON]

All the manufacturers we've used supply the data books at least on CD if not also on paper which still has certain benefits you don't get on the screen. They're less hesitant to send out the CDs since they're so cheap, but they might not send you a paper book (let alone a set of books) if they sense you're a hobbyist who only wants $5 of parts. You can still buy actual data books from places like Jameco. When I ask a manufacturer for a CD, they often say "you can get the data online." My response is, "It's too slow."

Eric, I'd suggest setting some smaller goals first. Do some learning, get some designing and building experience, and make the more basic mistakes on something small. That way you're more likely to succeed at your final, more grandiose goal later. Don't ignore the timing diagrams, propagation delays, and capacitances. You'll only get away with it at low speeds (2MHz and down). Come back to the forum and ask questions often. You won't be the only one learning.

Fortunately with today's parts, you'll be able to make your Apple II equivalent much smaller, cheaper, and has fewer parts and runs faster on far less power than what was possible when the Apple II was in production. For example, a single 512Kx8 SRAM or 1Mx8 EPROM will cost around $15.

Garth