My first KIM-1

In 1978 I bought my first computer, a KIM-1. It turned out to be a Rockwell rebadged Rev F Mos Technology board.

The beginning of lots of fun, learning, member of the KIM gg Club and making and publishing in the dutch electronics magazine Radio Bulletin and the KIM Kenner.

In 2014 the big KIM-1 machine was finally taken down in parts, the following photos showed the end result as in 1985 after many years of tinkering.

The KIM-1 system ended as a real production system until 1985, mainly to write articles, all Radio Bulletin and KIM Club Magazine related work was done with this system.
Then a CP/M machine took over (a Spectravideo X’Press 738) with the same VT100 as terminal.

  • KIM-1
  • 8K RAM  in system case
  • 32K RAM in expansion case
  • Two ACIA 6850 serial system
  • A PIA/VIA card with two 6820 PIA’s
  • Parallel ASCII keyboard with home made logic circuit
  • Video Display 32×32 uppercase characters on an analog TV
  • Dual cassette tape system with motor control
  • MDCR digtal cassette system in second expansion case
  • Radio Grafisch Display in second expansion case
  • Heathkit H14 matrix pinter
  • VT100 Digital Equipment Video display unit
  • Boot tape to load device drivers and Micro Ade (extended to 8K)
  • Micro Ade editor, used for program development and article authoring
  • Microsoft Basic KB-9 (not used often)
  • Pascal-M compiler and interpreter (mainly development and experiments, not production quality)

First the KIM-1, I still have it, in working condition, in my private museum. Changes still visible, are a red acryl cover over the LED displays, a capacitor moved to the back to make it flat enough to fit the case I made and some supports to have it lay stable and safe on a table.

Why a KIM-1?

In 1977 I was reading in the electronics magazines about the revolution taking place: 8 bit microprocessors!
During my study I encountered Digital Equipment machines, PDP-8 in the lab, PDP-11 in the Mathematic Computer Science department, a Minc in Medical Physics group, my major.
The electronics department where I was doing an intern not only introduced to digital electronics and I helped them to introduce the Z80 to the instruments designed for laboratory experiments.
I learned assembler quickly, PDP-11 was a dream come true, the Z80 a bit of a nightmare but you could do so much with effort.

At the same time I started to write for the magazine Radio Bulletin, simple analog and digital circuits and continued to be an editor until 1987. I met Dick de Boer who was writing his famous Microprocessor articles and introduced the KIM-1 to the Dutch electronic engineers. So a KIM-1 with the very attractive 6502 was the logical choice for my first microprocessor system.

First case: memory, connectors, power supply

A KIM-1 itself was fun to learn with, but it quickly needed more; a permanent power supply, protection, easy to access connectors and interfaces for  a bus to have  more memory.

So the case seen in the next figure was built:

Power hungry, so lots of lineair power supplies with large cooling.

The first case I built from alu profiles contained the KIM-1, a backplane for 6 memory boards, a lot of power supplies (lineair, so heat was a problem!), a patch panel to access the expansion connector, cassette I/O, serial interface and various switches.

PCBs handmade, double sided!

Memory 2K RAM Card, BEM Bus Brutech Variant made by Hans Otten
Memory boards were made myself by drawing with Edding ink on the blank PCB, etching and drilling. Filled with 2102 RAM IC’s for 1K per board, it filled lower RAM of the KIM-1 $0400 – $13FF. The bus is a 31 pin DIN connector, based upon the BEM (Brutech) bus.

The next thing I built was a video display unit. All TTL 74XX logic IC’s, a 2513 character generator, a AY-5-1013 character generator, an ASCII keyboard, display on TV 32×32 characters uppercase. RS232 input/output to the KIM-1.
On top of the VDU a dual cassette deck is shown. From the famous Dutch dump shop Radio Service Twente two audio cassette decks were bought, some audio amplifiers and power supply added, and a remote control circuit via a 6532 GPIO line (standard as in Micro Ade). Served me well for many years, in 2014 the decks strings were dried out and crumbled after many years of not being used.

Next was a real expansion cabinet with a long backplane for 32K memory with 8x 4K RAM card, 2114 based, Designed by me, published in Radio Bulletin and sold by Visser Assembling Electronics. BEM bus compatible.

4K SRAM card

4K SRAM card, Radio Bulletin September 1979 part 1  part 2

Production 4K RAM card

Prototype 4K RAM card, also hand drawn on the PCB!

In the expansion cabinet three slots were added for I/O. Two cards were designed by me and published in Radio Bulletin: an ACIA card for two 6850 Motorola ICs, and a PIA card for two PIAs, 6522 or 6520 or 6820 or 6821. I never used more than one ACIA and one PIA card. Shown are the prototype cards, in the article production quality PCBs were used.

PIA and VIA card design by Hans Otten June 1984 Radio Bulletin

ACIA Motorola 6850 by Hans Otten, 1983 Radio Bulletin

On one of the ACIAs a VT100 Digital Equipment terminal was connected, taking over from the bit banged serial interface and the homebuilt video display. ON the other ACIA a Heathkit H14 matrix printer was added, a mediocre but adequate printer.

Together with Micro Ade as assembler and editor, the dual cassette deck, 40K RAM In total, this was a nice machine! Until 1987, when I bought the Spectravideo X’Press 738 MSX and CP/M system, used for all my publishing activities.

A third expansion cabinet was built around 1983. It was driven by the PIA’s, the Radio Bulletin Grafisch Display was inside the cabinet, along with two MDCR Philips Digital cassette recorders, alo published in Radio Bulletin. The speed difference between Hypertape audio cassettes and 2400 baud MDCR speed was not that impressive.

Dirk Dral

EPROM card (Dirk Dral)


KIM-1 Software

On this page my collection of KIM-1 software in binary format , manuals and articles, from my tapes and scanned paper archives and user contributions.
Most require an expanded KIM-1 with RAM memory above $2000, 16K recommended. Of course the Micro-KIM and the Corsham KIM Clone and the PAL-1 with memory expansion have enough horsepower to run this.
See the page for useful programs to convert binaries to papertape etc.
Not all have been tested, some use non-standard TTY I/O routines, so study, test, experiment and have fun!

KB-9 and KB-6 are the name used for the Microsoft Basic for the KIM-1. One of the 6502 family of early interpreters by the then called Micro-soft company. KB stands for KIM Basic, the 6 and 9 for the precison of digits.
See here for the page about the KIM-1 binary versions , articles, listing, sources and build-and-enhance- it-yourself version.

Focal-65 V3D

The FOCAL programming language Version 3D (26 aug 1977) for the KIM-1.

A small interpreter (about 5K) for a convenient interpreted language. Floating point 9 digit accuracy. Two versions were distributed, one by Aresco and another by the Program Exchange. Included was a source listing, which I do not have.
Requires memory from $2000 and up. May have some terminal echo problems, see below in User Notes 13.
Based upon the DEC FOCAL8 language for the PDP-8, as defined in the Manual DEC-08-AJAB-D.
Programmed by the 6502 Group , read here the background of the creation of FOCAL-65.
Program and manual
The scanned manual, Aresco version
Disassembled source by Paul R. Santa-Maria
Introduction to FOCAL (dutch, KIM Kenner) by J. Janssen page 1, page 2 and page 3
Introduction to FOCAL, 6502 User Notes 12
Improve on echo problems with KIM TTY, from 6502 User Notes 13
Make room for enhancements, extend to 8K, from 6502 User Notes 14
Speed it up, from 6502 User Notes 15
Cassette save/write an LED display listing, from 6502 User Notes 16
Move FOCAL 65-E into EPROM page 1, page 2, from Compute II Issue 3


The FORTH language 6502 FIG-FORTH

Binary Forth original, start at 2000
FORTH assembler sources, 6502, 65C02
Fig-FORTH 6502 manual
Fig-FORTH Manuals May 1979

Tiny Basic

Tom Pitman’s Tiny basic. Small enough to fit in th 1K KIM-1, yet a real Basic interpreter

Tiny Basic binaries,
low memory version is tiny3, load address 0000 start address 0200
high memory version is tiny 1 load address 0000 + tiny3 load address 2000, start address 2000
Tiny Basic manual as pdf
Tiny Basic manual as html
Tiny Basic manual as text file
Tiny Basic Experimenters kit as pdf
Tiny Basic Experimenters kit as html
Tiny Basic Experimenters kit as text
Getting the most of Tiny Basic.pdf
Articles on tiny Basic from 6502 User notes
Source of Tiny Basic, monitor, and Tiny Basic Bill O’Neill
Tiny Basic for CC65 assembler sources
Tiny Basic games, such as adventure
Games for Tiny basic from Dr Dobbss Vol 1 Page 1, Page 2
Articles from the dutch KIM user Club:
KIM Kenner 10 Tiny Basic, tips how to save and load and change prompt, Hans Otten.
KIM Kenner 23 Tiny Basic, Filip van Kenhove, adapt to Elektor Junior


COMAL is an interpreted structured language. I have only as original the KIM User Club Elektor Junior version, and as with most of the 6502 SBC programs, not that difficult to adapt to a KIM-1, as shown in the last pages of the manual (in/out/break character, load/save tape, memory layout).
KGN COMAL binary
Manual KGN COMAL (dutch)
COMAL Introduction

MICRO-ADE assembler/editor

Updated November 2021

MICRO-ADE was the working horse for many KIM-1 users, the small and powerful assembler/editor/disassembler written by Peter Jennings, Microware.
Manual and program are placed here with permission by Peter Jennings to the KIM Club (thank you Peter for this and for a great program!)
A letter sent by Anton Muller, KIM User Club the Netherlands, to Peter Jennings, thanks Peter for the scan!

In August 2021 I (Hans Otten) typed in the source of MICRO-Ade from the listing in the manual, the output is binary compatible with the binaries I saved from tape and are tested on the KIM-1.
The result is a source identical (in standard MOS Technology assembler format) to the listing and binary identical to the page image. I also made new high quality scan of the manual and the listing.
Micro Ade program source and binary
Scanned manual
Scanned listing

Read in the KIM KENNER archive the source of the enhancements (text by S.T. Woldringh o.a.)
The KIM club enhanced Micro Ade to version 8. Download here the binary with a 2 page command summary.

Microchess for the KIM-1

Updated November 2021

MICROCHESS for the KIM-1. Another Peter Jennings Microware product. Runs on a standard KIM-1. Control via LED displays and hex keypad. Quite a commercial success, many sold!

Wave files of tape and binaries, dump of my cassette files
Assembler source and binaries, typed in by me in 2021, binary identical to tape
Original manual (from the reseller The Computerist) scanned by me
Original manual by Peter Jennings
Manual in HTML format
Article on upgrading/extending Microchess, Compute II Issue 1, pdf format
Article on upgrading/extending MICROCHESS, Compute II Issue 1, html format
Upgrade/extending assembler source and binaries, typed in by me in 2021
More chess openings, Fer Weber 1978

6502 Macro Assembler and Text Editor CW Moser

CW Moser ASSM/TED Assembler and Text Editor binaries: original, KIM-1, Elektor Junior
Manual scanned in PDF format

Color version of later manual
Dissecting C. W. Moser’s ASSM_TED, Compute! Issue 11
Commodore PET version of the manual
Graphics Drawing Compiler for PET and SYM manual
Fast cassette interface for ASSM/TED by CW Moser
Universal 6502 Memory Test PET, Apple, Sym and Others, Compute! Issue 1

KIM Tape Copy v1.1

kim tape copy v11 KIM Tape Copy v1.1, copy all files on a KIM cassette. Uses two recorders attached as shown in the Micro Ade manual.
Source in Micro Ade format
Listing of Tape Copy

H14 printer and parallel keyboard routine

The Heathkit H14 printer is a simple matrix printer with a serial interface. This routine allows to use this printer via two pins at the free 6530 PIA port, see circuit diagram. Resistors are 2k2 ohm.
H14 printer and parallel keyboard input assembler source
Lsiting and crcuit diagram

Printing disassembler

Printing disassembler, load and start address is $B000
Source of disassembler
Requires a parallel keyboard for character input at the free 6530 PIA port. H14 printer output if print is requested. See above for the H14 printer routine.

Q-Chess for the KIM-1

Q-Chess for the KIM-1. Requires 8K memory and a TVT-6 display. Via ptaching a TTY can be used.
Manual, including TTY patches
Binaries of Q-Chess for TVT-6 and for TTY
Patches on Q-Chess by Fer Weber, De 6502 KENNER 17 – augustus 1981

Usurpator Chess for the 6502

Usurpator Chess for the 6800 and 6502 in 2K, a book by H.G. Muller
The book, with source listings for 6800 and 6502
Source in CW Moser format


Time your reaction. Standard KIM-1 LED display and keypad. Source included.

First Book of KIM sources

The First Book of KIM-1 in PDF format
The First Book of KIM-1, part in text format
The First Book of KIM-1 in HTML format
Sources of The First Book of KIM-1 in source and papertape format,
Jeff Tranter
Software from First Book of KIM in binary, audio (Wave) and papertape format, by Dave Willams.

KIM Venture

A (tiny) Colossal Cave adventure for the KIM-1 by Bob Leedom


HEXPAWN, a game for the KIM-1 by Robert Leedom


Baseball, a game for the KIM-1 by Robert Leedom

Telefonbuch Hobbycomputer #1 Herwig Feichtinger

Telefonbuch Hobbycomputer #1 Herwig Feichtinger


Pascal-M: A full (1978) Pascal P2 descendent compiler system for the KIM-1.
See the School of Wirth pages for more information, including sources and binaries

Pocket calculator for the KIM-1/h3>

Siep de Vries Westvries Computing The Netherlands

1977Simple calculator (integer 6 digits positive) + – / *
I/O via TTY or keypad/LED display, the same method
as used by the KIM-1 monitor.
Two versions (scans included):
a special publication from the first days of the

KIM Club in a traditional 6502 assembler

and a later version for the Micro ADE assembler editor.
Sources included of both versions (TASM 32),

with resulting listing and papertape and Intel hex files.
As close to paper original, changes due to assembler quirks.
Download here Sources, papertape, listings, original scans

KIM-1 manuals

On this page:

– Essential KIM-1 manuals delivered with a KIM-1: User, Programming, Hardware, KIM Hints, most in English, some in German.
– Circuit diagram poster
– Reference cards
– MOS Technology Cross assembler
– First Book of KIM
– Some basic articles

User Manual

User manual in HTML format
User manual in text format
User manual in PDF format (note page 18-25 of the ROM listing is missing)
Appendix with complete ROM listing in PDF format
Corrected page 17 of ROM listing
Revision of Rockwell KIM-1 User’s manual
Customer Errata Letters
Customer Errata Letter 1
Customer Errata Letter 2
Customer Errata Letter 3
Proofreading version of User Manual from Terry Holdt
MOS KIM-1 Handbuch, German version of KIM-1 User manual

Hardware manual

Hardware Manual January 1976 Second Edition Publications Number 6500-10A
Hardware Manual in ASCII format
MCS6500 Hardware Manual jan 1975 in PDF format
MCS6500 Hardware Manual jan 1976 second edition in PDF format
Hardware manual in HTML format
Rockwell 6500 Hardware Manual
MOS 6500 Hardware Handbuch
German version of Hardware manual

Programming manual

High-res quality typeset manual by Pickledlight. Local copy. Check to original for updates!
MCS6500 Microcomputer Family Programming Manual
MCS6500 Microcomputer Family Programming Manual Hardcover
Programming Manual
Programming Manual in PDF format
Programming Manual in HTML format
Programming manual appendix in HTML format
Rockwell 6500 Programming_Manual
MOS Microcomputers Programmier Handbuch,
German version of Programming manual

6502 Reference Cards

6502 Reference Cards collection
MOS Technology Reference Card, better quality, early one, ROR instruction missing, handwritten

MOS Technology Cross assembler

Scan-160408-0001 Cross assembler Manual, GE timeshare

KIM Hints

KIM hints
KIM-1 Hints PDF format
KIM-1 Hints smaller PDF format
KIM-1 Hints in text format
KIM-1 Hints in text format with additions and corrections

Circuit diagram poster

KIM-1 circuit diagram
Rockwell branded circuit diagram
KIM-1 poster in high resolution, large picture!
Redrawn KIM-1 circuit diagram

First Book of KIM

First Book of KIM
The First Book of KIM-1 in PDF format
The First Book of KIM-1, part in text format
The First Book of KIM-1 in HTML format
Sources of The First Book of KIM-1 in source and papertape format, Jeff Tranter

KIM-1 user guide and notes from Microcomputer Principles

KIM-1 Userguide
KIM-1 user guide and notes from the book “Microcomputer Principles featuring the 6502/KIM

Quick Reference by Jeff Trenter

KIM-1 Quick Reference by Jeff Trenter


Jolt and Super Jolt

On these pages some information on the Jolt and Super Jolt are presented, the result of a Internet research for Jolt, Super Jolt and Microcomputer Associates. Microcomputer Associates company played an important role in the 6502 SBCs, TIM, KIM-1 and SYM-1 all contain results of their work. It continued as Synertek Systems with the SYM-1 and more.

Jolt page

Super Jolt page

Microcomputer Associates page


KIM-1 Clone

A KIM-1 clone build by Bob Applegate of Corsham technologies.

Somewhat inspired by the microKIM by Vince Briel, who was inpired by Ruud Baltissen! The idea is replace the 6530’s with 6532 and by carefull memory decoding have the I/O, timer and RAM of the 6532s appear at the same locations as the 6530-002 and -003. ROM is added with an EPROM.

Not an exact copy, the ROM has been changed/enhanced with a KIM Monitor by Bob, though the original KIM-1 ROM should work also.



With the name SUPERKIM an engineer called Paul Lamar designed a SBC around the 6502.
The main design decisions were to be a superset of the KIM-1, requiring no alteration of KIM-1 programs or user interface (the keyboard/display!) but with much more extendable resources. And the result is just right, it Is a KIM-1 with many improvements!
I have never seen this system in real life here in the Netherlands, only advertisements in the then current, dedicated to the 6502, magazines.

The heart of the system is the 6502 at 1 MHz and the well-known KIM-1 RRIOT’s 6530-002 and 6530-003,  the six  seven segment led  displays, a keyboard equivalent tot the KIM-1, the cassette interface and RS-232-C serial interface.  Extra are 4kRAM (from 1K on the KIM-1), 4×6522 VIA’s, 8K EPROM , all socketed and not populated by default. A 8 bit priority encoded IRQ and space for wire wrapping on the board. Also included are fully decoded address map lines, tri-state buffers for address and data bus on wire wrap headers and a power supply for 12V, 1A input ging 5V and 12V.

The KIM-1 ’emulation’  is complete, since the KIM-1 6530’s are there, at the default location and relevant KIM-1 hardware like seven segment display and keyboard, audio cassette interface and tty interface and edge connector.

The SUPERKIMwas sold by Microproducts as shown in this advertisement page in the magazine Micro, issue 13 June 1979:

Paul Lamar initially developed Road Test Systems with the KIM-1 and the limitations in resources made him develop the SUPERKIM.

Articles describing the use of the SUPERKIM in robots and Road Test systems:

IEEE: Microprocessor based System for roll-down and acceleration tests. LA-UR 78-3234 D.K. Lynn, C. Derouin and P. Lamar

Articles about the Computerized Road Test System from Lamar Instruments

From the blog of Dennis Simanaitis:


I came upon some photos summarizing automotive testing as practiced when I arrived at R&T in the late 1970s. One photo brought back memories of the excitement, the technical expertise, the glamor.
Weighing a test car, c. 1979.
We weighed our test cars at a local builders supply. The idea of having our own scales capable of obtaining individual corner weights was far off in a digital future. Rough and ready though the scene appeared, the supply-yard scales were California-certified and nearby.
Track testing took place at Orange County International Raceway, a local drag strip with abbreviated road course. A fabled place: Bob Bondurant used it for his first driving school, opened in February 1968. The second week, Bob had two students: actors Paul Newman and Robert Wagner, both preparing for the movie Winning. P.L. Newman continued, racing and winning.
In 1977, R&T’s John Dinkel, my predecessor as engineering editor, asked a fellow named Paul Lamar whether any new computerized gizmos might be employed in gathering acceleration and braking data.

John Dinkel, at the wheel, and Paul Lamar examine computerized data. (That’s their story; and they’re sticking to it.) This and other images from R&T, May 1977.

Paul is a cool guy. Beginning in 1966, he worked with Texan Jim Hall in developing the Chaparrals 2C, 2D and 2F. (Paul was responsible for most of the body design of the 2F.) After that, he set up his own company doing race car development and equipment design. For a long time, he has been active with aircraft applications of Mazda rotary engines, at a website proudly “Powered by Linux!”

Back in 1977, Paul said to JD (as Dinkel was known), “I recommend you consider a microprocessor. It’s the coming thing in electronics.” Paul followed up on his recommendation with devising the first computerized test equipment used by an auto magazine. Hitherto, acceleration testing was a two-person task, one driving, the other punching an array of stopwatches based on measurements of a bulky 5th-wheel.
Another gizmo, the sainted R&T Tapley Meter used to give impressive data with which we younger readers were highly impressed (“Wow! Off-scale!”), though we never really understood what it was measuring. (It turns out the Tapley Meter was a pendulum-driven accelerometer.)
When I began at R&T in early 1979, Paul’s computerized black box became an everyday part of my track testing. Its heart was an MOS Technology MCS 6502 Microprocessor Array.
The “sixty-five-oh-two” was pivotal in the computer industry: Its price was one-sixth that of comparable products and brought about a rapid decrease in competitors’ pricing and a dramatic increase in microprocessor availability. In retrospect, it likely had the computing power of a toy digital clock operated by a potato battery, but at the time it was state-of-the-art.
The Lamar black box had a keyboard for programming. (How’s your base-16? Mine is sketchy at best.)
The Lamar black box’s keyboard was one of its ways for entering a program—in hexadecimal (base-16) code! Fortunately, once debugged, the acceleration and braking programs were stored on a separate Sony
cassette tape recorder and played back into the 6502 when changing from one test to the other.
Alas, the black box had insufficient memory to store them. Also, reprogramming turned out to be occasionally heat-sensitive: I would do the acceleration testing, say, then turn on the car’s a/c to cool off the interior for a bit. Only then would the Sony convey its bops and beeps successfully to the black box.
The 6502’s liquid crystal displays gave information on time, car speed and distance traveled. The Sony cassette tape recorder to its right swapped the 6502’s programs.
Sensitive though it could be, the setup was more accurate than stopwatch-punching and it was a one-person operation. Results were printed on a strip of paper by a separate device, a modified Addo desk calculator residing on the passenger seat. (Paul’s second-gen black box had a built-in printer and enough memory to eliminate the pesky reprogramming.)
Typical results from a separate printer, a modified Addo desk calculator.
The Lamar 5th-wheel was decidedly easier to use than its traditional counterpart. It weighed 20 lbs. versus the clunky one’s 40 lbs. and attached with bungee cords, not potentially bumper-damaging clamps.
The Lamar 5th-wheel compared favorably with its traditional counterpart. It could also be disassembled for shipping.
In 1986, I documented our testing procedures in a presentation to the Society of Automotive Engineers, SAE Paper 861114, “A Magazine’s View on Automotive Testing.” The paper was accompanied by a short film completely produced by R&T, a story in itself. This was back before video cameras—and ages before smart phone imaging.
R&T’s Cecil B. “Joe” DeRusz shot the flick using an Arri Arriflex 16-mm camera, the best of its kind, rented from a Hollywood outlet. We had a vague shooting script based on the technical details of the SAE Paper. But I have vivid memories of Rusz figuring out angles, the entries into frame and exits out of it. I recall we produced the film in a few days of on-again/off-again shooting. Likely over budget. There were lunches after all.


In a two part article in the magazine Robotis Age 1980-1981, Don McaAllister describes the interfacing an programming of the SUPERKIM for the control of the Lour Control ET-2 robot shell.


The Computerist

The Computerist


The Computerist Hardware

The Computerist was a company founded by Robert M. Tripp.

On this page information on the PLUS hardware for KIM-1, AIM 65, SYM-1.. Updated April 2022 with contributions by Friedrich Hofmann.

Memory PLus van Dirk Dral, met 8K Basic in EPROM.

MICRO the 6502 Journal

Archive of the magazine Micro here.

From description of MICRO 6502 Journal:
Robert M. Tripp got his start with computers in 1960 as an undergraduate in an unrelated field. He found the computer programming so interesting that he became a programmer in 1969, and started with the 6502 microprocessor in 1976, initially with the KIM-1 trainer sold by MOS Technology. He started a business, “The COMPUTERIST”, and sold the KIM-1 computers, as well as software and accessories for it. He started a magazine under the umbrella of his business, and named it Micro. It began publication in October of 1977, and was released on a bimonthly basis initially, going monthly in February of 1979. The first three issues were printed using his KIM-1 and he did the paste-up for the magazine on his kitchen table. He later began to use a local publishing company to create the magazine. By early 1980 the publisher name had changed to MICRO-INK, Inc.

The magazine covered the 6502 microprocessor (and later the 6809) in all the various computers that used it, including the KIM-1, the AIM-65, the C1P, the Commodore PET, the Ohio Scientific, the Atari 800, and, of course, the Apple II. It was an excellent source for machine level code for the 6502, eventually including more and more articles that applied specifically to the Apple II. Ultimately, about half of the articles in each issue dealt with the Apple II.

Many general-purpose machine language articles appeared in its pages, such as “Improved nth Precision” (code optimization for the 6502), “Precision Programming”, and “Computer Assisted Translation Of Programs From 6502 to 6809″. They also carried do-it-yourself hardware articles, such as “C1P To Epson MX-80 Printer Interface”, “PET/CBM IEEE 448 To Parallel Printer Interface”, and “Apple II Digital Storage Oscilloscope”.

Hardware by The Computerist

The Computerist, led by Robert Tripp, not only sold software like MicroChess,  published the Micro Magazine, also designed and sold hardware.

The Dutch company, Ing. Bureau Koopmans (a one man company, active in the early years with KIM-1, OSI Scientific and such) represented The Computerist in the Netherlands, and he showed me in 1979 some of the Plus hardware series for the KIM-1, SYM-1 and AIM-65 systems:
– MEMORY PLUS: 8K RAM, 8K ROM, VIA 6522, 2716 EPROM programmer
– Proto Plus, a DIY board
– VIDEO PLUS, a glass teletype video card

I did a review of the Memory Plus in May 1979, see also the dutch magazine Radio Bulletin page.

PLUS Hardware

A range of hardware was developed and sold by the Computerist, under the brandname PLUS.



Motherboard Plus

A backplane for KIM-1/SYM-1/AIM 65. Accepts the Plus boards described below.

Memory Plus

The MEMORY PLUS board is a RAM/ROM expansion board for  KIM-1, SYM-1 or AIM65. Made by the The Computerist.

With up to 8k of RAM, 8k of (EP)ROM and the ability to program EPROMs (2716) this was quite the must have upgrade for anyone who could afford it.

Here The Manual in HTML format, original OCRed by Lee Davison, corrected and enhanced with Appendix A Circuit Diagram and Application Note #1 by Hans Otten.

Scanned by Dirk Dral, high quality scan.

And here the MEMORY PLUS manual in PDF format, Appendix A, the circuit diagrams  foldout Application Note #1 is now included, added by Hans Otten.

How to decode the 8K RAM in 4K space, an article from Micro July 1979, for AIM 65 and SYM-1 

Video Plus

VIDEO PLUS is designed to work with the KIM-1, SYM-1 and the AIM 65 computers. It offers:

  • Up to 4K  display RAM and 2K Programmable Character generator
  • 2K EPROM
  • 6845 CRT controller
  • ASCII keyboard interface
  • Composite monochrome video PAL or NTSC

The following documents are available:


Video PLUS II is an updated Video PLUS, a Versatiel Video Expansion Board, with:

  • Programmable Screen format
  • PRogrammable Character Generator
  • Uo to 4K Display Memeory
  • Supports ASCII Keyboard
  • Stand-Alone Option
  • AIM/SYM/KIM Software
  • 6845 video controller, 6522 VIA, RS232

The following documents are available:


The PROTO PLUS II is a board to interface digital logic to a KIM-1, SYM-1 or AIM 65. A large breadboard area is available.

The board has the standard KIM-1 44 pin edge connector. A power regulator for 8V to + 5V is on the board.

The board has  address, data bus and signal bus buffering and address decoding for tom select a 8K page in memory and kIM-1 8K decoding. 3 gates of a 74LS32 is available for general use.

Here the PROTO PLUS II manual, with circuit diagram.




DRAM Plus is a Multi-purpose Expansion Board for AIM 65/SYM-1/KIM-1 with

  • 16/32K dynamic RAM
  • 8/16K EPROM 2716/2516/2732/2532/2332
  • I/O Ports and Timers VIA 2x 6522
  • Prototyping Area
  • EPROM Programmer

DRAM PLUS manual, includes circuit diagram and software



K-1002 8 bits DAC
An 8 bits DAC. For the PET userport, easily adapted for other 6502 systems.
Hardware K-1002 manual includes circuit diagram

Files for the VIDEO and PROTO PLUS: Thanks to Dave Colglazier at Original Woodworks.

Video PLUS II and DRAM PLUS: thanks to Friedrich Hofmann


The Micro-KIM is a SBC designed and built by Vince Briel. First sold in 2007 and alas not available anymore.
Based upon the ideas of Ruud Baltissen how to replace the 6530 with a 6532, it was the first KIM-1 clone that was running the unmodified KIM-1 ROM.

Manuals, circuit diagrams, single step fix, tape devices, support Cd images


  • 6502 CPU running at 1Mhz
  • 2K EPROM replacing built in ROM on 6530s
  • 5K RAM using the KIM-1 memory map
  • RS232 interface made to work with TIM built in KIM-1
  • Single-Step mode for debugging
  • debounced RESET and STEP switches
  • 40 pin header for future expansion
  • Expansion board for expansion connector with four slots available
  • 32K RAM card
  • Second 6532 board
  • The I/O of the 6 digit display and keyboard are memory mapped exactly like the KIM-1 for full program compatibility

See the KIM-1 page for more KIM-1 info and programs.

First impressions

  • It really feels like a KIM-1. Smaller, but just as simple to operate. Easy to connect a serial RS232 (USB) cable and connect to a terminal program. Minicom on Linux, Realterm on Windows e.g., no high demands on terminal emulation, just plain simple teletype at 9600 baud or less and the ability to capture output to a textfile or send a text file via the terminal
  • No cassette port. This means the programs with real nostalgic value like the editor/assembler Micro Ade will not have much sense.
  • Second 6532 is an option(though the 6530-002 and 003 ROM is present!).
  • 32K RAM extension option. Yes, this makes the machine worthwhile! Now you can run KB9 Microsoft Basic or otehr KIM-1 software.
  • Some small mistakes are on the version 1 Rev 0 board, fixed in the later version rev 1, this needs three hardware fixes to be made, so I have to get the soldering iron into action. Simple fixes, see below.
  • Loading programs via the serial interface by sending a text file in papertape format is slow. But it works! Fun to test all those KIM-1 programs. KIMTAPE and KIMPAPER help a lot here also look at the 8 bit hex file conversion program there.

Tested programs

Most of the First Book of KIM programs work. Some require the presence of the second 6530 (6532 here).
See the KIM-1 software and manual pages. Also see the photos section for TinyBasic and KB 9 Basic.

See the KIM PC utilities page for papertape and other conversion utilities.

Memory map

Micro-KIM KIM-1
$0000-$03FF 1024 Bytes of RAM $0000-$03FF 1024 Bytes of RAM
$0400-$07FF 1024 Bytes of RAM $0400-$07FF Optional Memory Area
$0800-$0BFF 1024 Bytes of RAM $0800-$0BFF Optional Memory Area
$0C00-$0FFF 1024 Bytes of RAM $0C00-$0CFF Optional Memory Area
$1000-$13FF 1024 Bytes of RAM $1000-$13FF Optional Memory Area
$1400-$16FF Optional Memory Area $1400-$16FF Optional Memory Area
$1700-$173F Optional 2nd 6532 I/O, Timer $1700-$173F 6530-002 I/O, Timer
$1740-$177F 6532 I/O and Timer $1740-$177F 6530-003 I/O, Timer
$1780-$17BF 64 Bytes RAM from 6532 $1780-$17BF 64 Bytes from 6530-003
$17C0-$17FF 64 Bytes RAM from 6532 * $17C0-$17FF 64 Bytes from 6530-002
$1800-$1BFF 1024 Bytes of EPROM $1800-$1BFF 1024 Bytes of ROM in 6530-003
$1C00-$1FFF 1024 Bytes of EPROM $1C00-$1FFF 1024 Bytes of ROM in 6530-002
$2000-$FFFF Unused memory $2000-$FFFF Unused memory or 32K RAM baord

* The 6532 has 128 bytes of RAM vs. only 64 bytes on the 6530. The Micro-KIM utilizes all 128 bytes from
the single onboard 6532 so all original memory locations are available.

Manuals, circuit diagrams, notes and support Cd images

Micro-KIM setup and Users Manual July 2007 Rev 0 Ed 1
Micro-KIM setup and Users Manual September 2007 Rev 1 Ed 2
Circuit diagram Micro-KIM rev 0, has serious errors
Circuit diagram Micro-KIM Rev 1
Support Cd contents Rev 0 July 2007
Support Cd contents Rev 1 September 2007
Fix for Micro-KIM Rev 0 for second 6532
Aart Bik’s programming the Micro-KIM, see also his KIM page

Extensions and audio interface solutions

65C02 Single step fix by Timali

My Micro-KIM shipped with a 65C02, and apparently there is a timing issue which prevents single-step from working with the 65C02. I tried an original NMOS 6502, and single-step worked ok with it, but not with any of my 65C02s. I did some debugging with my scope and determined that there is a small timing difference causing the SST signal to be erroneously asserted (pulled low) for 100-200 ns during EEPROM accesses with the 65C02, which is just enough to cause a problem. The easiest way I could think of to fix this was to delay the SYNC signal briefly with a small RC circuit, which prevents the glitch in the SST signal. I cut a trace on the back side of the board and added a small resistor and capacitor, and single-step is now working correctly with my 65C02’s. It still works with the original 6502, also. Click on the image to see a larger picture.


Tiny Basic

Microsoft Basic KB9