KIM Uno - 6502 emulated on Arduino

Submitted by gerry on Thu, 12/04/2014 - 13:25

When I was young, about 11, I was lucky enough to be bought a Commodore 64, the computer that introduced a generation to computers, and likely launched thousands of careers in computing, mine included. It wasn't long before I started to feel constrained by the very basic version of BASIC that it ran... 2 character variable names, no labels, no loops apart from FOR, no allowances to structured programming whatsoever. However, help was at hand, in the form of theCommodore 64 Programmer's Reference Guide, and Jim Butterfield's Supermon 64 machine language monitor. I remember keying in Supermon 64 from the pages of Compute! magazine... my mentor and educator for many years, and remember clearly the vast speed increases to be had from running machine language code versus BASIC.
Since then, things have changed so much... I do much of my coding in Python and Java running on multi-cored monsters that live in air conditioned data centres, and capable of speeds that are beyond ridiculous, and yet I still feel a great deal of nostalgia for simple CPUs that can be coded directly with no scheduler or process management to be concerned with. Arduinos deliver some of the fix I miss, as does the Raspberry Pi, but I really miss the 6502.

One day, while browsing, I came across a site, Obsolescence Guaranteed, wherein the site owner described his adventures in creating an emulation of the Computer That Started It All, as far as I am concerned. The KIM-1 was released by Commodore in 1976, when I was 5, and had little more than a CPU, a bit of memory, a hexadecimal keypad and display, and a serial port. Not exactly a monster or performance by today's standards, but back then, when you could easily blow a couple of hundred thousand on a PDP-11, or a few million on a 'big iron' System 360, this little thing was a revelation, and cheap at about $250.

Oscar, of Obsolescence Guaranteed seems to have as much fondness for old quirky computers as do I, but the KIM-UNO, basically an emulated 6502 and RAM running on an Arduino Mini Pro, with a simple circuit board for the keypad and display, was what really caught my eye. On getting in touch, I found out that a new run had been ordered and should be ready for shipping within a few days. Providence! It was clearly meant to be, so I paypal'd €25 for the kit, and a box and USB-TTL cable, and 6 or so days later had my prize.

I strongly recommend the documentation be read before beginning, or a critical step may be missed. Aside from that, it's a simple build, albeit with loads of solder joins to be made for the keypad. An hour or so of soldering and it's done, ready to be started up... (yes, I know some of the leads could be trimmed better, but I need to get a new side-cutter).

KIN UNo

So back to my roots, I go.

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