Understanding the Apple 1's Function

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Stargeezer's picture
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Understanding the Apple 1's Function

Hi All:

I have a goal for 2024. :-)

I am not an electrical engineer by trade or education, only by interest, which means I am not an EE.

One of the goals I set for 2024 is to take my electronics understanding up a notch.  I am good at soldering and building things orther have designed but designing something on my own or truly understanding what is happening in a board (one that doesn't use a RasPi or Arduino, etc).....whole different ball game.

I have a fairly good understanding of the electronics basics, passive compenents, logic circuits, truth tables, ohms law, etc. Just about everything Forest Mimms has taught me........lol

So I decided I would like to take a stab at understnading more by looking at early Apple computers, specifically, understanding at a deeper level how the Apple 1 works.

I know there will be posts that discourage this or say I should do things differently or I am jumping ahead to far, etc and that is fine, I am open minded, but have a goal.

As such, does anyone have a recommendation for a good book that explains the Apple 1?  Its design, how the logic works, etc., not its history or lore.

I have looked at the Operations manual and other documentation, but they don't have enough explanation.

Perhaps what I am seeking doesn't exst?

I have found various sources talking about different bits and bobs, or its role in Apple's history, or how Woz talks about it in "iWoz", but nothing that says "Hey, were going to walk throught the Apple 1 from power on to program execution.  How the keyboard works and provides input, what happens in the CPU, and how it makes it to stdout, etc"

I figured someone here might know where to point me.



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Well I'm hardly an expert but

Well I'm hardly an expert but here's what I know.


The Apple 1 didn't really sell huge numbers, so I don't think there were any contemporary books on it. I know there's a book on how the Apple 2 circuitry works. That book probably has a lot of knowledge in it that's *also* relevant to the Apple 1.Book is "The Apple II circuit description" by Winston Gayler.


The Apple 1 is made of two portions, a "computer" portion and a "terminal" portion. These sections work mostly independent. There is some bridging IO so the Apple can send characters to the terminal portion but that's it. You can send characters and a newline.


The computer portion of the Apple 1 is mostly quite "boring". I remember way way back in the day this page helped me understand 6502 computers a bit more: https://lateblt.tripod.com/6prj1pic.htm Hopefully reading it will give you some insight.


I'm not entirely sure how similar they are. But from what I gather the terminal portion is quite similar to the "Tv typewriter" by Don lancaster. Even if the designs aren't quite identical I'm fairly confident understand the TV typewriter will help you understand the Apple 1 terminal portion better. https://www.tinaja.com/glib/bdtvtype.pdfThe original TV typewriter articles are available on the internet.


It's hard to be more specific on what skills/knowledge you need to read up on to understand more since I don't know how much pre-existing knowledge you already have.


I hope the above helps you on your quest!


edit: also if your goal is purely to learn more electronics. I would recommend *designing* your own stuff instead of trying to understand other people's stuff. Eventually designing your own stuff will give you the skills to better understand other people's designs. Goal could be to say, build an Apple 1 clone with modern parts.

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There is no good book explaining the Apple-1 circuits --- yet.

In post #1, stargeezer wrote:


" As such, does anyone have a recommendation for a good book that explains the Apple 1?  Its design, how the logic works, etc., not its history or lore. "


Uncle Bernie responds:


I've written a thorough analysis of the Apple-1 circuitry with all the fine points (i.e. the "recovery mode" where it scrolls away fake cursors, nobody else seems to know about this). This was meant for an Apple-1 book. Which never made the progress it should have made. I intended to document and explain all the exisiting peripherals (both those designed by others and those designed my me) but as the market for such a "book" is very small, my motivation to proceed with this work got weaker and weaker. Instead, I got sucked into the Apple II world with all this MMU/IOU replacement work, and now I'm developing an Apple IIe replica, and have no time left for the Apple-1. But this new work may bring solutions to the various problems still plagueing my Apple-1 color graphics card and my Apple-1 floppy disk controller card, which have their own threads in this forum. All these do work, to some extent, but none of them is as perfected as I want them to be, and both require some mods to the Apple-1 motherboard, which were not planned to be needed at all. I also saw different behaviour of these cards when plugged into my fourteen Apple-1 clones. This is not good. And so far the quirky nature of the Apple-1 has conspired against achieving the goals I had with these projects. For instance, the addresses on the expansion bus get trashed / invalid / bogus whenever its on-board DRAM is activated. This is a built-in "feature" of the Apple-1 motherboard but it has bad consequences for my color graphics card, the "write-through" feature I sought did not work (the various Apple II graphics modes work fine, though).


In my "Replica IIe" prototype I have some experimental circuits which may help to rectify these issues with my Apple-1 color graphics card. And once everything works as intended I might be more motivated to complete this book. Alas, my flying hobby as a private pilot also has suffered greatly due to the pandemic:I made no progress with added ratings in the past 4 years, and had to abandon the pursuit of the "Instrument Rating" just a few hours before being ready for the FAA checkride, because my flight instructor started to caugh the deadly virus on me, and I can't fly on instruments when wearing a military grade respirator. Now I'm basically back to start. So I will need more time for that hobby, too. But what can I complain - I got away without losing my livelyhood or my health (I did not take that diabolical "vaccine" either - there were too many red flags that it's not what they claimed it to be - the complete immunity from product liability lawsuits and criminal prosecution for little transgressions like plain mass murder given by governments to the manufacturers alone was already enough to prove it's too dangerous to take, at least for people who are able to think critically and analyze the known facts).


This said, I can't guarantee my book on the Apple-1 will ever be completed. But if I find the time needed to complete it, I'll publish it, probably as a cheap book-on-demand. Did not test the waters there yet, but there seem to be Chinese based companies who can produce such books at reasonable cost, and handle all the sales. In the end, you could order the book on Amazon or elsewhere and this sets a process in motion (without any involvement of mine) which ends with the book appearing in your mailbox. As I don't need to make any profits, I would be fine with that solution. As long as I don't need to spend any of my RQLT with financing, warehousing, packing and shipping books myself, anything goes. (Note that traditional publishers will NOT touch the Apple-1 technical topic under any circumstances. I tried. Was told market being too small.  Same issue with books on rare collectible cars or rare collectible guns. Typically, real enthusiasts publish such books which may be of interest a few dozen people in the world on their own dime, taking the losses. But I don't want neither profits nor losses. Read "Atlas Shrugged" to find out why.)


- Uncle Bernie


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You can't learn how the Apple-1 works by use of modern ICs.

In post #2, "Jero32" wrote:


" Eventually designing your own stuff will give you the skills to better understand other people's designs. Goal could be to say, build an Apple 1 clone with modern parts. "


Uncle Bernie comments:


The first sentence is true, I fully agree with that. The second sentence is a fallacy. You can't build an Apple-1 clone with modern parts. Because the typical MOS shift register based architecture or the original Apple-1 is a thing of the late 1960s / early 1970s and was already technically obsolete when Woz designed the Apple-1. As for Don Lancaster's TV typewriter of 1973, it uses the same basic MOS shift register architecture as suggested by manufactureres of these MOS ICs (i.e. look into the Signetics "1972 MOS Silicon Gate 2500 Series / Metal Gate 2000/2400 Series Databook", where all the 2504/2513/2519 of the Apple-1 are found in great detail). The basic architecture of the "video data path" in the TV Typewriter and the Apple-1 is the same. But as far as I can tell, Woz rolled his own video timing circuits (the counter chain) and his cursor state machine also looks like "Woz TTL IC magic" to me. At least I could not find any prior art coming close to it. Unless proven otherwise, I am inclined to assume that these important subsystems of the "Terminal Section" are genuine, innovative, and were conceived by Woz himself.


If you want to build an Apple-1 with modern parts, look no further than Vince Briel's "Replica 1". Tom Owad offers the book he wrote on its construction on the Applefritter front page. It is worth to have in any case. There are lots of interesting stories about early Apple-1 users like Lisa Loop. But this book will not explain anything about the original Apple-1 circuits.


- Uncle Bernie

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Thank you to all for the awesome feedback

Uncle Bernie:  I would totally buy your book.  I also didn't get the "vaccine."  A long time ago I was an ICU/CCU and cath-lab nurse.  I too saw too wasn't impressed.  If you have to keep getting boosted over and over and over, it isn't a vaccine, its a treatment regemine, and a poorly effective one at that.  But we digress.


Thank you Jero32 for your insight and suggestions.

I think in the short term, until your book is published, I'll start with "The Apple II circuit description" by Winston Gayler, "Apple II Reference Manual", and "Understanding the Apple II."

I don't have any interest in building an Apple-1.  Some of my inspiration to understand the logic circuits came after listening to "iWoz".

I like your idea to stary designing my own stuff.  Old school trial and error.  Love it.

Thanks again all.


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Ben Eater has a long series

Ben Eater has a long series on building a 6502 system and has a video that dives into the specifics of WozMon. This might be a fun and inspiring jumping in point. https://www.youtube.com/watch?v=SpG8rgI7Hec

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Apple IIe

Curious, is there a book similare to "The Apple II Circuit Description" by Gayler, but for the Apple IIe?


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Jim Sather, Understanding the Apple IIe

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Thank you

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Hi Mark,I recognize myself in

Hi Mark,

I recognize myself in your post. I am also not an electronics engineer, but very interested in how the stuff works.

A couple of years ago I started the project of creating an Apple-1 clone. Still not finished. I like to understand what I make first, that's why it takes such a long time. I enjoy the learning curve a lot. I created an ASCII Keyboard Tester with the goal to understand the part of communication between the keyboard and the computer and still have more ideas to discover other parts of the Apple-1 at an electronic level.

I found the TV Typewriter Cookbook by Don Lancaster pretty inspiring. It came before the Apple-1 but the electronic workings of the terminal section, cursor movement, and display of characters on the TV screen is comparible to the Apple-1. Ben Eater's YouTube video's are great as well. I personally like Usagi Electric's YouTube channel as well.

It would be neat if someone describes the workings of the Apple-1 in a book, I would be interested for sure.

Take care, regards from Holland,




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Usagi Electric
nijssen wrote:

I personally like Usagi Electric's YouTube channel as well.

I love that channel too: variety of content, epic projects, historical perspectives, and technical explanations make it always interesting. And David's enthusiasm is wonderful.


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Next Steps

Hi All:

Moving along with this.

I purchased Don Owad's book and have been reading over other tomes like Understanding the Apple II, etc.

Thank you to everyone for the feedback and thanks @nijssen for your Ben Eateer suggestion.  I have followed his channel for some time and he has made a huge diffeence in my understanding.


I would like to take anothe small step in this project and have pcbs made.  I haevn't decided if I will build a full on replica, but want to start with a PCB, it may only become wall art, but who knows.  I have used JLCPCB often and like their work and it sounds like others here have had boards made there as well.

There is a 2020 post form @mi2k https://www.applefritter.com/content/apple-1-replica-gerber-files that provides a set of gerber files.  However, mi2k later said these gerbers have some minor issues.  If I just hang it on a wall, these issues are not substantive; however, if I decide to build one they may become an issue. 

Other posts on AF suggest that the "Newton" board is the best, but they are no longer available as I understand it.

I would like to do a run of boards as I may want to have more than one......one to hang and one to build, etc.

So a couple questions please:

1) What are the best open source Gerbers available?

2) Are Newton gerbers open source?

3) Are Willegal's mineo board gerbers open source?

4) Which of the all open source gerbers would folks recommend?

5) Are gerbers available for the cassette interface board?






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Hi Stargeezer!

Lots of questions, I'll try to answer all of them. 


1.  No idea, since they are open source, lots of people have tried to edit them. I've collected a dozen replicas (a bit carried away, I know!) on the gerberas you listed in the link above. These are a primary source for a project by my friend Misha Mdesk from Moscow. They are indeed not perfect, but only cosmetically (transition hole diameters, contact pads, font, etc), and electrically correct. If your choice is in their favor and you do everything right, your replica will work 100%. They have been assembled dozens of times all over the world. 

2. Newton boards from Hong Kong are not an open source project. You can buy them on eBay. These boards are more accurate than open source, their surface has some relief, and in general they are usually bought for serious, high-precision copies where every element matches the original. I have such a board, I can take some pictures for comparison with the open source board.

3. Mike Willegal's Mimeo is not an open source project either. They've been out of stock for a few years now, but they too tend to be highly accurate copies for serious projects. 

4. See point 1.

5. Yes, Misha Mdesk's ACI boards were not very accurate originally, but I managed to convince him to help me edit them a bit. How it turned out is probably not for me to judge (I personally like it! ). It's also an open source project, you can check it out here on Applefritter.




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For a good understanding of Apple 1 Hardware

For a good understanding of the Apple 1 hardware operation look here:  Apple 1 information

Use the nav arrow in the upper right to navigate the pages.

Check out Apple 1 Terminal this is the best overview of the Apple 1 video section that I have ever found!




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start with this book - it

start with this book - it would be difficult to understand the Apple 1 without understanding the 6502 first.





Mike Willegal-

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