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74 votes
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How did Woz write the Apple 1 BASIC before building the computer?

TL;DR: As explained on Steven Weyhrich's great and authoritative Apple II History Site, Wozniak simply sat down and wrote his Integer-BASIC (*1) on paper, while assembling it at the same time by hand. ...
Raffzahn's user avatar
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40 votes

How did Woz write the Apple 1 BASIC before building the computer?

One thing is certain: Steve Wozniak was very good at hand assembling 6502. Instead of writing assembler mnemonics he could simply type in the necessary hex code. I realize this isn't a proper answer ...
George Phillips's user avatar
38 votes

Was there ever any real use for a 6800-based Apple 1?

At the Homebrew Computer club in Palo Alto, California (in Silicon Valley), Steve Wozniak, a 26 year old employee of Hewlett-Packard and a long-time digital electronics hacker, had been wanting to ...
snips-n-snails's user avatar
21 votes
Accepted

Why was the original Apple Computer labeled as the Apple I?

Development happened very rapidly in the first two years of Apple. Wozniak did the Apple 1 in 1975 and the Apple ][ in 1976. When the Apple 1 was first presented to the world at the Homebrew Computer ...
Brian H's user avatar
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20 votes
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Did the Apple 1 cassette interface card have its own ROM?

The Card featured 256 bytes of ROM. Is there evidence documenting how the cassette program was stored? The evidence is right there in the PCB photo you added. The two MMI 6301 chips, labled APPLE A3 ...
Raffzahn's user avatar
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15 votes

How did the Apple 1 video circuit work?

Preface: The whole circuit isn't complicated, but quite involved. I will try to use 'normal' language to make it less hard to read, as mentioning all the signals and interaction would end in an ...
Raffzahn's user avatar
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13 votes

How did Woz write the Apple 1 BASIC before building the computer?

Woz was exceptional, but not the only one with this (moderate level of ?) skill in machine language. Lots of teens/kids learned to poke (from Basic) absolute hex machine code into memory on several ...
hotpaw2's user avatar
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10 votes

Why didn't Wozniak's interrupts work on the Apple I monitor program?

My two cents: I have written a lot of code with interrupts, and failed many times. Interrupts are very difficult to debug because they are asynchronous, you cannot easily enforce the same conditions ...
Martin Maly's user avatar
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8 votes
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How did Woz get the Apple 1 monitor program into ROM?

At that time he worked at HP, where they had of course the needed promer - the only drawback was that he had to walk to another building, as you already cited (in another question) from iWoz: I ...
Raffzahn's user avatar
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8 votes
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What were the modifications on the Apple 1 board that would have made it 6800 compatible?

The 6502 works with a single square wave clock signal that is connected to Phi0 pin 37. The chip has a built-in clock generator to use this clock input to internally generate two anti-phase non-...
Justme's user avatar
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7 votes

Why was the original Apple Computer labeled as the Apple I?

As we all know, the Apple I computer didn't last very long as it was supplanted by the hugely successful Apple II about a year later. Let's start with the fact, that it was labeled Apple 1 not I. Not ...
Raffzahn's user avatar
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7 votes

Could suitably-written Apple-I software force bytes into the display shift register, and do modern recreations emulate that?

Video output runs via a 6821 PIA and the interface exposed to the CPU is fairly simple: peripheral register B is configured so that the highest bit is an input and the low seven bits are an output. ...
Tommy's user avatar
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5 votes

What is the format of the Apple 1 character set ROM?

Original ROM The character ROM is a Signetics 2513 "64×8×5 Character Generator," a 2560-bit static ROM. (Data sheet alternate source.) Address lines A1-A3 (Signetics started the numbering at ...
cjs's user avatar
  • 26.7k
5 votes

Apple I and II video output to a contemporary TV set?

Most CRT-based television sets sold in the US will accept any combination of horizontal sweep rate that's within a few percent of 15.75kHz and vertical sweep rate that's within a few percent of 60Hz, ...
supercat's user avatar
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5 votes

Was there ever any real use for a 6800-based Apple 1?

[Caveat: This question asks for opinions and guesswork] The 6800 was a well proven and widely avaible CPU, while the 6502 was brand new with an unclear future. More important, there was next to no ...
Raffzahn's user avatar
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4 votes

Were any Apple 1s sold with non-ROR 6502s?

In this video from an auction service, the 6502 fitted is clearly shown (eg. at 2:05) as a white-ceramic packaged example with a 1576 datecode, corresponding to early April. This is before the ROR ...
Chromatix's user avatar
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3 votes

Why was the original Apple Computer labeled as the Apple I?

The Apple 1 was a single design, but multiple products There were multiple incarnations of a particular computer design that would eventually be called the Apple 1: Wozniak's prototype boards. ...
DrSheldon's user avatar
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3 votes

Were any Apple 1s sold with non-ROR 6502s?

For the second part: But was there any other software sold or widely shared that deliberately worked around the ROR bug? The most prominent may be Microchess, originally developed for the KIM but ...
Raffzahn's user avatar
  • 226k
1 vote

How did Woz write the Apple 1 BASIC before building the computer?

I would like to note that it was the hand-entered code that ultimately did in Integer BASIC. Jobs demanded floating point for the II, and although Woz had already written an FP library by that point, ...
Maury Markowitz's user avatar
1 vote

Were any Apple 1s sold with non-ROR 6502s?

On the AppleFritter forum I happened to ask "Did the original Apple 1s built by Apple have the ROR bug?" and Cory Cohen ("Cory986") replied: Yes they did. Only the last boards out of Apple had a ...
cjs's user avatar
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