An Arduino From The Distant Past

Arduinos are a handy tool to have around. They’re versatile, cheap, easy to program, and have a ton of software libraries to build on. They’ve only been around for about a decade and a half though, so if you were living in 1989 and wanted to program a microcontroller you’d probably be stuck with an 8-bit microprocessor with no built-in peripherals to help, reading from a physical book about registers and timing, and probably trying to get a broken ribbon cable to behave so it would actually power up. If you want a less frustrating alternate history to live in, though, check out the latest project from [Marek].

He discovered some 6502 chips (Polish language, Google Translate link) that a Chinese manufacturer was selling, but didn’t really trust that they were legitimate. On a lark he ordered some and upon testing them he found out that they were real 6502s. Building an 8-bit computer is something he’d like to do, but in the meantime he decided to do a project using one of these chips as a general-purpose microcontroller similar to a modern Arduino. The project has similar specs as an Arduino too, including 8kB of RAM memory, 8kB of I/O address space, and various EPROM capabilities. [Marek] went on to build a shield board for it as well, for easy access to some switches and LEDs. It’s a great build that anyone interested in microcontrollers should check out.

Keep in mind that an ATtiny45 has 8 bits like the 6502 but only costs around $1 USD, whereas a 6502 would have cost around $200 in today’s dollars. It’s really only in modern times that we can appreciate the 6502 as a cheap 8-bit microcontroller for that reason alone, but we can also appreciate how it ushered in a computer revolution since competing Intel and Motorola chips cost around six times more before it showed up. They became so popular in fact that people still regularly use them to build retrocomputers of all kinds.

20 thoughts on “An Arduino From The Distant Past

  1. Mos Technology was selling the 6502 for $20 per unit, which made it stand out. Even Byte put $20 in the title of the article where they first talk about. Really great for hobbyists, but I suspect less important to others. It lured in Steve Wozniak, who of course was just building a computer that others could build too.

    It did contrast with other CPUs at the time, which had high single quantity prices, probably offset by free samples if you were an existing company. Legend has it that the bare Altair 8800 was about the price of a single 8080, allowing for people to throw away the computer and still have a CPU, but MITS had to get a much, much better price in quantity, since they had to pay for the rest of the parts etc.

    Nobody ever talks about quantity pricing of the 6502, but surely that had to happen too.

    Of course it keeps on going, a lot of embedded use, so the price kept going down. If it can be had for a dollar now, how much was that in 1975 prices?

    There were other 8bit CPUs that saw much less attention, and rarely made it into “home computers” though they must have seen controller use. But nobody mentions their pricing.


  2. Around 1984 we had to make a board with a 6502, it was double the size of this one :)
    I remember besides the 6502 a PIA(parallel interface adapter with DDR, i think), little RAM, an UV-erasable EPROM for the program which had to be programmed on another ‘machine’. It was programmed in pure assembly, no labels, only hex numbers and offsets. We had a whole year to work on, and in the end we had a working clock and temperature display. :)

      1. That’s the 65C02 which is slightly different (and what was actually used in the project). I’m impressed he got real NMOS 6502s from China – I thought they were hard to come by (and in demand for old arcade games and the like that don’t work with 65C02s).

        1. I was also surprised. I expected nothing more than receiving useless, counterfeit chips. But the thing is – they do work and current draw is consistent with NMOS technology. They look old, showing scratch marks and signs of being pulled out of sockets and then washed. It would be very strange to put so much of an effort to manufacture operational fake chips, which are identical with the original, but then to sell them for less then one dollar. I’d rather guess someone recycled large amount of them from some old e-waste…

          In fact I ran into a problem with fake Chinese 6502 once, but situation was a little bit different. I ordered some cheap Rockwell R65C02P4 chips on eBay. I received the order. Parts were operational, but current draw was suspiciously high for a CMOS chip. There was also no support for new instructions. Probably they were relabelled MOS6502…

  3. I think I need to clarify. I do not claim that person selling those chips manufactured them. It was just a seller. Parts were probably disassembled from some kind of a device or had spent last few decades in some storage room. They look old. I didn’t open them but current draw and heat emission is consistent with what you should expect from an original NMOS version of 6502. There is also a lack of support for some new opcodes, that were introduced in CMOS version.

    I think it would be too much of an effort to emulate all of that features to simply put M0 inside DIP40 package and the sell it for a dollar or so. :)

    1. Thanks for the answer. I just read the article above and assumed these are new.
      AFAIK when you have a semiconductor production line, silicon surface area is more valuable than a one-time SW development. So, producing an old and big CPU seems uneconomical when you can make tiny, modern MCU dies.

  4. Go find a JDR Microdevices catalog from 1989 and you’ll see they were selling 6592, Z80, and other popular processors for five or ten bucks. Ww haven’t had THAT much inflation since then.

    The “Arduino” of that time waa the Motorola 68HC11 evaluation board. Many a student learned to program with its BUFFALO monitor. I still have one somewhere.

      1. Right. Actually, the big breakthrough for Arduino wasn’t the hardware – the Atmel AVR series had been around for a while by then. The breakthrough was the software, essentially a free C++ compiler and IDE. The early C compilers for 6811, 8051, PIC, and AVR were prohibitively expensive for the “let’s see what I can do with this” hobby market. I used 8051 and 8048 series in the early 90s, and was starting to dabble in 6811. I wrote an assembler for each of these in BASIC, because that was pretty easy. The real issue was the learning curve that came with each new family, and the fact that you had to rewrite all of your libraries.

    1. The HC11 was a nice step up from the 6502 for small projects. They were all the rage on the Seattle Robotics Society’s website. I remember scratching my head with Forrest Mims’ Postscript compiler for it.

  5. I remember, as a 1970s high-school student, trying to grock timing diagrams and figure out how to build something beyond a 555 astable vibrator. I failed completely because one required an EE degree and physical docs to accomplish such magical things. About a decade ago, I returned to my childhood hobby and discovered the Arduino and its ecosystem. Having had a career as a programmer analyst in the interim, I loved that one could approach the Arduino platform from a high-concept perspective, find libraries in the Internet to help with the fiddly bits, and create a sophisticated project in a day.

    It truly was the Dark Ages when I was an aspiring, child tinkerer.

    1. Yes. Dark ages. There was a big gap between the days of 8-bit CPUs and systems you could hack with relatively little intellectual misery, and the return of microcontrollers with the Arduino universe. I blame two things for this: protected memory machines, starting with the 80386, which required writing device drivers because the OS owned all of the peripherals, and USB, which was designed from the start to be hard to break into. But the light has returned. And the funny thing is, a lot of people are looking at those old 8-bit platforms again, even though we now have 32-bit systems that are almost as easy to develop on.

  6. Actually:
    $25 in 1974 → $127.40 in 2019
    I bought a 6502 on the first available day from Chuck Peddle for $25. The Rotate Right instruction didn’t work, but I didn’t NEED it :-) Built a physically big machine, all wirewrap including a floppy disk controller. Learned a Lot.

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