I want to learn how the 6502 works

[bluejay]

To give a bit of an introduction, I'm no adult. I'm far from being one. I'm reading (auto)biographies of people like Steve Wozniak, and reading about them build computers like the Apple I and Apple II from the ground up, alone. Of course, Woz is a very talented engineer, unlike me, and he had years of experience in designing electronics. And designing a fully blown computer is very difficult. I want to do that kind of stuff but I'm always stuck at square one: I don't understand how these work in the first place.

So I thought, what better opportunity than now to learn electronics, when I have tons of time at home. I have found various website that taught me what capacitors and resistors and transistors are and do, but I can't find one that describes how a simple microprocessor works. From my understanding the original Apple II manuals describes the Apple II and peripherals well, so I'm planning on reading through those, but is there a good resource on learning a simple microprocessor like the 6502(or maybe something even simpler). Better yet, if someone here's willing to teach me from square, that'd be amazing.

So, where can I learn how the 6502 works? Hopefully after some training I'll be able to build something that resembles a computer someday:) Thanks!

Edited April 21, 2020 by bluejay

[bluejay]

I'm currently reading through the original MOS manuals. Seems pretty legit, describes all the stuff well like a good manual!

[+Stephen Moss]

Sounds like you are probably already on the right track, the 6502 data sheet is where I would start. If it is well written it should explain every you need to know and will probably have the Assembler mnemonics at the back (as many PIC data sheets do) so that you can start programming, if not try searching for a programmer reference manual.

I have not looked but I'm sure there will be emulators you can use the test your code on.  

[+DrVenkman]

There are tons of resources beyond bare manuals:

 

http://www.visual6502.org

 

http://6502.org

 

And some real 6502 nuts have done this, which every fan should see and marvel at:

 

https://monster6502.com

[zzip]

Here's a site where you can enter your own 6502 assembly and run it in your browser:

https://skilldrick.github.io/easy6502/

 

From the site DrVenkman posted, this visualizes what is going on inside the 6502 as it executes code:

http://www.visual6502.org/JSSim/index.html

 

 

[bluejay]

Thanks for the help guys! It'll take a while to read through all the manuals but time's what I've got:)

[emerson]

I would suggest finding a copy of '6502 Assembly Language Programming' by Lance Levelthal. If you google 'atarimania 6502 leventhal' you should be able to find a pdf download. While searching for the leventhal book I found another one that might be interesting, try searching 'atarimania interfacing the 6502'.

[Keatah]

There's an overwhelming amount of material available. Don't be discouraged if one book doesn't "fit" you. There's always another. And once you get going you'll start combining bits of this book and sections of that book.

 

If you're programming on an Apple II why not look through:

ftp://ftp.apple.asimov.net/pub/apple_II/documentation/programming/6502assembly/

Or if you're doing it on the Atari VCS:

https://atariage.com/forums/forum/31-2600-programming-for-newbies/

 

I learned programming through the 4 Apple manuals that came with my II+. To a kid back then it was like an advanced college course. After that I got a few select printed books from the bookstores, when they existed in the malls in the 80's. All of it was eminently more readable (and valuable) than the shit they forced on us in high-school. Who the hell wants to know about invisible dead men in the sky or stories of even more dead men riding horses through mud..?!? Pfttttblech!!

 

Edited April 22, 2020 by Keatah

[bluejay]

The Apple //e books I have doesn't seem to be as high quality as earlier Apple machines' manuals. Bummer!
I'm using manuals I found online and printing out the important ones(MOS Hardware manual, programming manual)

Thanks again for the help!

[Armitage]

https://eater.net/6502