Retro Computing

AIM65-CPLD-3V3 for sale

Labu Asabu made 5 units of the AIM65-CPLD-3V3 for sale.The price is 55,000 yen for a full set + accessories.Shipping ...

aim65_quartus, an FPGA clone

Filippo (shinymetal6) published an alpha version of aim65_quartus, an FPGA clone on his github resource.Forum discussion on the MisTer forum ...

Scan of book Microprocessor Systems Engineering

NEW: Scan of book Microprocessor Systems Engineering, by R.C. Camp, T.A. Smay, C.J. Triska Only the AIM 65 System 65 ...

TIM-1 SBC

Christian Ortner (mister-freeze at the VzEkC e. V. forum build a SBC with expansion around a TIM IC. Here ...

MTU K-1008 Visible Memory in the KIM-1 Simulator

On request of Dave Plummer the MTU K-1008 Visible Memory is added to the KIM-1 Simulator, a new version V1.2.0 ...

AIM 65 reproduction AIM65-CPLD-3v3 manual

The page on the AIM 65 reproduction AIM65-CPLD-3v3 by Yasushi Nagano (Labo Asabu) has now a manual. Quite a large ...

AH5050 floppy disk system for AIM 65

In 1983 the company ABM sold a floppy disk system, Commodore IEC 1541 based, for the AIM 65. It ...

ESCO added detailed information

wikokom (Willi) posted additional information about his ESCO system.Also images of his first KIM-1 in a suitcase~ and current KIM-1. ...

KIM-1, MTU Visable Memory, and Memory Tests

https://www.youtube.com/watch?v=eA3TtCCNmKo

EMUF and MC Die Mikrocomputer-Zeitschrift

The EMUF pages are a tribute to the work of the editing staff of the German magazine MC Die Mikrocomputer-Zeitschrift ...

AIM 65 keyboard replica

Ralf (ralf02, forum64.de) obtained a working AIM 65, alas without the keyboard.So he designed and build one. In his own ...

KIM-1 PCB replica Eduardo Casino

Eduardo Casino has designed with modern tools, like Kicad and image software Inkscape a PCB for the KIM-1 which is ...

AIM 65 clone updates

Mr Nagano published videos and photos of an early prototype of his AIM 65 clone.

ESCO SBC

User wikokim on the forum.classic-computing.de bought this system in 1978/79. He published documents and ROM dumps.See here for this 'KIM-1' ...

KIM-4 photos

I received photos from Joseph Avins of a KIM-4 motherboard connected to a KIM-1.Added tot the KIM-1 hardware pages, read ...

RSC-Forth computers

The R6501Q and R65F11 IC's I acquired are Rockwell parts for single chip computer systems. Well, they contain a lot ...

Elektor Junior VIA 6522 German

Found in my archive: the German version of the Elektor Junior VIA 6522 book.Added tot the Elektor books page.

ZIPtape for KIM-1

Glen Deas sent me an article about the Ziptape cassette interface, 1978, by the late Lew Edwards. Glen made a ...

John Bell Engineering

The page on John Bell Engineering has been expanded to a page per SBC, to keep the information accessible. See ...

My retro toolchain

Development for my old 8 bit retro SBC's has become much easier with fast PCs and good tools. All cross ...

This page is about my interest in retro 8-bit small computer systems computing and electronics. And the role of Dutch electronic magazines like Elektuur and Radio Bulletin in the eighties of the 20th century. Also the Dutch users club, called KIM Gebruikersclub, which I joined in 1978 and contributed to as member of the board and as chief editor of the magazine issue 11 to 25.
The retro computing pages are documenting my experiences with 8-bit systems like the KIM-1 and its relatives such as the Apple 1 and the Junior. And various small Z80 and other systems.
I set up this archive as my personal archive of what I research on the subject. If it is of any use for others, fine, enjoy!

Magazines

In the early days of computing, magazines about popular electronics played a big role in making microprocessors available for the beginner, whether the professional or hobby electric engineer. The magazines featured here are the dutch magazines Elektuur and Radio Bulletin. From 1977 until 1996 I worked as technical editor for Radio Bulletin and published about microcomputers and more general electronics. Elektuur published also articles on these subjects, many are available here.

What is a SBC for me?

A SBC, short for Single Board Computer can be defined as a computer system, based on a microprocessor, on one printed circuit, with keyboard and display, programmable I/O ports, expansion connectors and without a casing. The ‘operating system’ is stored in a (EP)ROM, an often small amount of RAM is available to store programs and data These were the first microprocessor based computers with affordable prices for hobbyists in the late seventies of the previous century. For professionals a way of getting acquainted with the new hardware and learning the basics of programming at a (very!) low level.

Though it is a complete computer, it has a CPU, memory and I/O, it is also a very limited one. The I/O is often not more than a small keyboard with hexadecimal functions. The display is often not more than 6 or 8 seven segment LED displays, just enough to show, in hexadecimal format, addresses and data. The operating system allows entering and examining of data in memory locations, and start and stop a program. Loading and saving data is limited to either papertape readers and punches, quite common in these days, or via some modulation as data files on audio cassette recorders. Also common is the ability to attach a teletype like the ASR33.

A good example of such a SBC is the KIM-1, shown below. 2K ROM, 1K RAM, many I/O lines free, six LED displays and a keyboard with hexadecimal keys and some function keys.
Why these SBCs like the KIM-1 became so popular? One reason was the low price ($ 280 for a KIM-1, I paid 795 guilders ), so it was in the price range of the average student and hobbyist. Another is the design being open, the complete hardware description and detailed listing of the ROM was included. And it is not the frightening computer, but more a programmable piece of hardware. Because it was so easy accessible and low speed, adding and changing hardware is not hard also. Programming was not easy, but editors/assemblers that could run with some added hardware like RAM and a video terminal made that possible. The nowadays common practice of cross compiling was not available for the hobbyist then.

Besides playing with the SBC, to learn what the microprocessor is capable of, many SBCs were put to work as a sort of PLC, controlling devices in the real world.
What changed the popularity of SBCs was the wish to transfer it to a computer with a better user interface, like graphics on a video screen, a full blown keyboard, a real operating system with mass storage such as floppy drives, and a higher fun factor, a.k.a. games. Or to make it a serious computer fit for business. So SBCs became extinct fast in the mainstream hobby world when the hobbycomputer appeared on the market, like the TRS-80, PET and later the C-64, MSX etc. Even later the boring business PC killed the hobby computer, but that is another story.
It seems the SBC’s are back though: Arduino and Raspberry Pi and the availability of cheap Chinese electronic shops and cross compilation on the PC make it possible to play affordable with small programmable devices at a lower level.

This site is mostly specialized on the 6502 and Z80 SBC (Single Board Computer), small computers based on an 8 bit microprocessor. Good for learning about digital electronics and programming at a lower level. And for many the start of their career in computer science.
SBCs featured here are systems like KIM-1, Apple 1 and equivalent boards like the A-ONE, Apple 1 Replica, Micro-KIM, Elektor Junior, AIM-65, SYM-1, RC2014, TEC-1, MBC-2 and such.

Please use the Contact form to contribute to this fascinating hobby!

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