The KIM-1 has two 6530 IC’s, the 002 and 003. From some research I have found that this factory mask rommable I/O RRIOT has been produced in more versions.
An interesting one is a relative of the KIM, the Terminal Interface Monitor 6530-004. Meant for a minimal 6502 development system, it contains a teletype oriented monitor program and a serial interface via bit banging.
See the TIM 6530-004 page for more information.
6530-002 KIM-1 listing in KIM-1 Users manual
6530-003 KIM-1 listing in KIM-1 Users manual
6530-004 TIM Terminal Monitor, see the TIM page
6530-005 According this OSI appnote this is an unprogrammed version of the 6530. I have seen ads for this part without description of what this is.
Terminal Interface Monitor, short TIM, with codename 6530-004, is a 6530 with a monitor program in the mask ROM.
No systems were sold by MOS around it, just a kit with manual and the IC. The Jolts use a TIM IC, Micro Associates, who designed the jolts write the TOM monitor for MOS Technology and called TIM DeMon. The DATAC 1000, a single-board computer based upon a 6502 and a TIM RRIOT, designed in 1976 by Philadelphia Area Computer Society club members Carmen DiCamillo and Roland James.
Many hobbyists build themselves 6502 SBCs around a TIM IC.
Here the machine readable and ready to assemble source, listing and binary of TIM (Thanks Martin Hoffmann-Vetter) Note that this contains a corrected version, version 2026! While testing the TIM Simulator I found an error in the papertape loader LH command, the ‘;’ start of a record seems to be OCR’ed to ‘:’ . In 2026 may OCR errors in the comments are fixed.
The resulting binary is identical to the ROM dumped from a real 6530-004.
The story of the TIM (from Ch.1.5 of “On the Edge: the Spectacular Rise and Fall of Commodore”)
The first development system offered by MOS, the TIM IC, was in kit form, which reduced the selling price to only $30. Since the unit was designed primarily to instruct the user on the workings of computer systems in general and the 6502 in particular, MOS Technology contracted Microcomputer Associates of Santa Clara, California to write the unit’s internal program. The two founders, Ray Holt and Manny Lemas, taught engineers how to use microprocessors. Peddle relates, “You have to understand how little the world knew of microprocessors in 1974, ‘75 and ‘76. There were guys making big money selling classes on microprocessors during that time.” Manny Lemas had worked for Peddle during his GE days, while Ray Holt had an impressive background working on the F-14 Tomcat project for the Navy.
In the middle Manny Lemas, on the right Ray Holt
The technicians developed the system in a special research area on the second floor of MOS Technology. The lab was a room within a room, with a large sign on the door in capital letters warning NO ADMITANCE. Inside, the team stared intently at oscilloscopes or sat over hot irons soldering components onto circuit boards. Small pieces of circuitry were scattered chaotically across the room. Since the 6502 microprocessor and supporting chipset contained almost everything necessary for a computer, the design was minimal. When assembled, it could be connected to a teletype machine or a computer terminal.
The biggest job was programming the built-in ROM code for the computer. This consisted of a debugger and monitor program, appropriately called the DeMon. According to Peddle, DemMn was programmed by Manny Lemas and Mike Quarter, who previously developed Peddle’s time-sharing system. The programmers used this time-sharing system to develop the code, which they burned into a 6530-004 RRIOT chip. This little powerhouse included RAM, ROM , I/O and timer capabilities.
The system was named simply. Peddle and his team liked acronyms, thus the Terminal Interface Monitor, or TIM was christened. TIM would begin a predilection at MOS Technology and Commodore for assigning friendly three-letter names to their products.
Those ordering the $30 development kit received the grey-ceramic 6530-004 chip and a manual consisting of 14 sheets of 11×17 paper, folded and stapled in the middle. Included in the manual were a suggested schematic, the TIM monitor commands, a few sample programs and a listing of the monitor code. It was up to the user to provide the resistors, transistors, capacitors, wire, and even the 6502 microprocessor.
Though receiving a computer in the form of a kit does not seem particularly user friendly now, hobbyists at the time clamored to build their own computer. Nonetheless, a good portion of the kits failed to operate upon completion. Rather than using a prepared circuit board, many buyers simply wire-wrapped the chips together on a piece of generic perf board or prototyping board, often termed a kludge board. After placing the required components on the board, builders hand wired the chips one pin at a time, resulting in a snarl of fine multicolored wires. Once the chips were in place, the user then had to construct or purchase a separate power supply for the TIM. Finally, the TIM was (as the name suggests) able to interface with a standard ASCII terminal or teletype machine.
As hoped, the do-it-yourself nature of the kits spawned familiarity with the products, and once hobbyists had invested time learning about the chip, they often remained loyal to the 6502. Many hobbyists ended up using their TIM computer as a small development system, since it was ideal for creating small programs. For their part, MOS Technology continued to sell TIM computer kits to diehard hackers, even after the Commodore acquisition. Ultimately, TIM was just a stepping-stone to developing and marketing a fully assembled computer.
Functions of the TIM software in ROM
• Self adapting to any terminal speed from 10-30 cps,
• Display and Alter CPU registers,
• Display and Alter Memory locations,
• Read and Write/Punch hexadecimal formatted data,
• Write/Punch BNPF format data for PROM programmers,
• Unlimited breakpoint capability,
• Separate non-maskable interrupt entry and identification,
• External device interrupts directable to any user location or defaulted to DeMon recognition,
• Capability to begin or resume execution at any location in memory,
• Completely protected, resident in Read Only Memory,
• Capability to bypass DeMon entirely to permit full user program
control over system,
• High speed 8-bit parallel input option, and
• User callable I/O subroutines.
DeMon’s Command Set Includes:
.R Display registers (PC,F,A,X,Y,SP)
.M ADDR Display memory (8 bytes beginning at ADDR)
: DATA Alters previously displayed item
.LH Load hexadecimal tape (socalled MOS papertape format)
.WB ADDR1 ADDR2 Write BNPF tape (from ADDR1 to ADDR2) (Intel papertape format)
.WH ADDR1 ADDR2 Write hexadecimal tape (from ADDR1 to ADDR2)
.G Go, continue execution from current PC address
.H Toggles high-speed-reader option (if it is on, turns it off; if off, turns on)
I know of several commercial systems using the TIM:
– The Jolt and Superjolt, Microcomputer Associates/Synertek (also information on the origin of the TIM-1 program!)
– the first Brutech BEM bus system, A small Dutch company, Vinkeveen, that produced professional 6502/6809 and more, industrial systems.
– Datac 1000
Frank Wolf has decapped a TIM 6530-004 to study it and maybe do a FPGA clone.
Here the photo’s:
Expand your TIM
TIM BYTES THE APPLE
(Design by Fred Hatfield, scans and transcription by Tom Owad, https://www.applefritter.com/node/2833)
For those of you that would like to have hard copy capability and much better control over program development on the Apple 1, the following hardware addition will accomplish it.
Using a 6530-004 (‘TIM’ chip) costing about $12.00 gives many superb features such as a variable baud rate serial input/output, a high speed parallel input (high speed paper tape reader), an excellent breakpoint processor, paper tape dump and load routines, etc.
The TTY port is located at locations 6202H and 6203H. Date at that port should be 00H and 16H respectively. The baud rate is stored at 00EAH and 00EBH and 110 baud is represented by 10H and 46H at those locations. It’s a fun addition to the Apple 1. Try it!
Fred Hatfield K8VDU
Teletype connection schematic.
Teletype Pinouts (connections 6530-004 and Apple bus):
TIM articles in the Micro journal in pdf format:
– Micro 1: Terminal Interface monitor (TIM), introduction and description, with am alternative system circuit diagram.
– Micro 3: TIM meets the S100 bus.
– Micro 9: Two short TIM programs. First a program to chage the baudrate, the second is a small operating system.
MOS Technology designed in 1975 two ICs that look very similar, the MCS6530 and later the MCS6532.
The 6532 is called RIOT, for RAM I/O and Timer. The 6530 is called RRIOT, for ROM RAM I/O and Timer.
The timer and I/O is (nearly) identical on both IC’s. RAM is 64 byte on a 6530, 128 byte on the 6532.
The ROM is where the big difference is, it is a 1K so called mask programmed ROM. This means the contents of the ROM are determined in the factory.
Besides the ROM, also at the factory choices can be made about the Chip and Register Select lines and such.
The 6532 is a general purpose I/O IC and widely used because of its versatility.
Of the 6530 a limited number of variants were made by the factory. The 6530 variant is often indicated by a number, 6530-XXX. Rockwell also used R3XXX and for Commodore diskdrives 9xxxxxx numbers were used also,
Well known variants are the 6530-002 called KIM and 6530-003 are used in the KIM-1 computer. The 6530-004, called TIM, is used in the Jolt and Datac computers. A ROMless variant is the 6530-005.
Pinball machines from Gottlieb and Allied Leisure used many 6530’s.
The Commodore Chessmate use a 6530 024 for I/O and chess openings. The early Commodore disk drives used 6530 in many variations.
Early Commodore disk drives used the 6530 also.
These ICs are hard to obtain now, production ceased in the 80ties. Clever persons created 6532 to 6530 adapters.
The 6530, nick named RRIOT is quite a special IC in the 65xx family.
Timer, RAM (64 byte), ROM, I/O, Counter in one IC. It has a factory mask programmed ROM and the locations of its I/O and RAM and ROM are determined also in the factory.
The 6530 is found in among others the KIM-1 (6530 02, 6530 03), a Chess system with MicroChess by Peter Jennings (6530 24) and variants are used in Commodore disk drives.
The 6532 has no ROM and RAM size is 128 byte versus 64 in 6530. I/O and timer are functional identical to the 6530. The nickname is RIOT, and it is a general purpose I/O device in the 6502 family. Very popular in e.g. the Atari 2600, and many clone KIM-1’s.
There is a datasheet for an IC called the 6531, RRIOC for RAM ROM I/O Counter. I have never seen it in the wild though, but seen references to pinball machines using it.
The DOS65 system, designed by the KIM Gebruikers Club, based upon an Elektuur Octopus design, augmented with a better floppy controller is now documented on the DOS65 page.
The dutch company Visser Assembling Electronics, Alkmaar, working for and in cooperation with the dutch carpet-factory Forbo Krommenie, developed a system based upon the KIM-1.
The T4 system consist of a large portfiolio of RAM, ROM, EPROM, input (Analog and Digital) and Output boards. Also a videoram card was developed.
The ALPHA-1, made by Berliner Unternehmens MCS (“Micronic Computer Systeme GmbH”) is an early computer, produced in 1977. The design is influenced heavily by the KIM-1 with many improvements and enhancements.
It is ready to run, has a KIM-1 compatible cassette file format. The system exist of an external CPU board and a cased display/keyboard I/O system.
About the Apple 1, and modern clones I have like the A-ONE and the Replica 1.
All of us older computer geeks know that before selling Macs, Apple founders Steve Wozniak (the genius) and Steve Jobs (the greedy business man) had a lot of success with the Apple ][ or Apple 2 or Apple ii, whatever marketing tricks were done with the name of that remarkable personal computer. The 2 in the name suggest there was an Apple 1 and yes, there were a very limited numbers of boards sold (200 or so, 50 or so survived time, so its a valuable collectible) branded Apple 1 in the 1976-77 time-frame. It has video on board and accepts input from a full size keyboard, so it is one of the first standalone hobby/personal computers based on a microprocessor, the 6502 of course, being powerful and cheap at that moment.
What is an Apple 1?
Besides being the first product of Apple Computers and designed by Steve Wozniak, the Apple 1 featured as one of the first a complete computer, with keyboard and video, on one board, based on an affordable and powerful microprocessor, the 6502.
Not many were build. The hype around it and the rarity make it one of the most expensive computer collector items.
My Apple 1 replica built by Armin Hierstetter
Apple 1 Replica
There are many Apple 1 clones made. Ranging from just an adaptation of the Wozmon, the monitor of the Apple 1 running on emulator or a 6502 based computer, to real Apple 1 SBCs replicas with the original PCB and (rare) parts . In between are the replicas where the complex original video circuit is replaced with a modern IC based, like Arduino or Propeller.
The Replica-1 by Vince Briel was the first to apply modern components to replace the hard to get and therefore expensive components, like the Signetics 2513 and such, with modern microprocessor emulating the complex terminal part. The terminal part is replaced by microcontrollers, for video and serial interface. Vince Briel designed quite a complex replica of the Apple 1. Complex because of the now defunct, hard to get components. He worked around that problem with innovative modern solutions and added modern connections like USB and PS/2 keyboard. The result is the Briel Apple 1 Replica range(SE, TE etc).
Available are a slot expansion for three real Apple 1 slots, a multi-I/O board with ACIA 6551 and 6522 VIA and, designed by Rich Dreher, the CFFA1 (Compactflash mass memory) board.
Here a collection of pages on the Apple 1 and Apple replica’s.
Of these Replica’s I have in my collection the Apple 1 Replica shown above, the Briel Replica 1 SE, the A-ONE (in all three flavors) and the RC6502. All still available!
And all excellent Apple 1 computers with some differences:
The Apple 1 Replica is the real thing, museum quality.
The A-ONE 2006 and even more the 2026 is a compact build with excellent video quality.
The A-ONE has a real Apple 1 slot instead of the pin header on the Replica-1 but in a shrinken format!
No parallel keyboard interface on the A-ONE, the PS/2 input functions as the parallel keyboard. On the Replica both parallel and PS/2 can be used.
Selection of NTSC or PAL on the A-ONE delivers a rock solid picture.
The Replica-1 has USB, also functioning as power supply, as an option also as serial interface. The 2026 A-ONE also has an USB power input.
The Replica-1 has an AT(X) power connector, required for the -12V of the parallel Apple keyboard (not on the latest Plus
The Replica 1 has a EEPROM, the A-ONE an oldfashioned EPROM.
The Junior computer design was published by Elektuur/Elektor from 1980 on. It was published in a series of magazine articles, four books and several so called paperware A4 booklets. And the ESS Elektor Software Services for the ROMs.
Loys Nachtmann designed and developed the Junior Computer, G.H. Nachbar did the Dutch translation of the German books. The 4 Junior books were translated into English, German, Spanish, Italian and French.
The Junior design is in fact heavily inspired by the hardware of the KIM-1 (or you can call it a copy!), the floppy disk interface design is a copy of the Ohio Scientific floppy disk interface design. Though I am not aware of copyright claims by MOS Technology/Commodore or Ohio Scientific, the inspiration is clearly visible.
It was delivered as a kit by shops or could be be built from the PCB’s (and later the ROMs) sold by Elektuur. Many hobbyists have build one, it was cheap and well documented.
Later extended with video card and an adapted version of the 8K KB9 Basic and even a disk operating system (Ohio Scientific DOS OS65D V3).
Articles in the Elektuur magazine and books (1-4), a 6522 book in the same series, in Dutch, English, French, German, Italian and Spanish were published.
Quickly adopted by the Dutch KIM Gebruikers Club because it was so close to the KIM-1. In the later days the number of Junior Computer users exceeded the KIM-1 users and changed the nature of the club from professional users to a hobby club. It also led to the DOS65 operating system for the Elektuur 6502 CPU board
The magazine Elektuur (the Dutch name) and Elektor (the name in the rest of teh world surprised us in 1980 with the publication of a build-yourself 6502-based SBC. It is a design in the tradition of the KIM-1 and SYM-1: a hexadecimal keyboard, six hexadecimal led displays and KIM-1 compatible tape format.
Many Junior Computers were built, either from the PCB made by Elektuur and separate components or as a complete kit. And after we (Anton Muller and me) sent a letter to the Elektuur magazine that got published about the KIM Gebruikers Club, many hundreds Junior users joined the club.
Developments after the Junior design was published in Elektuur led to the EC65(K) (see the Elektor Computing books) and the KIM Club DOS65, documented on this page.
Developed by Mos Technology. later acquired by Commodore, to show the possibilities of the 6502 microprocessor but quickly discovered as the first mass-produced personal computer. Easy to extend, lots of detailed documentation. With assembler/editors, first Microsoft Basic on cassette and even a Pascal compiler, it could do a lot. The first have an original Mos Technology logo, later versions have the Commodore logo on the board, small technical differences other than more recent 6502 IC’s without the infamous ROR omission.
This prehistoric computer has no “real” keyboard and no video output, program are entered by the small hexadecimal keyboard (located in the lower right part of the picture) and results are displayed on the small LED “screen” (it can display only 6 digits). It has a simple monitor that allows one to examine, modify memory, load and save paper tape, load and save cassette tape, run and debug programs through a ‘single step’ mode. The monitor works with the built in keypad and LEDs, or a terminal like the Teletype ASR33. This 20 mA current loop is easy to adapt to RS232C and so any videoterminal can be used.
The KIM-1 design inspired many designers of 6502 systems, mimicking either the unique LED and keypad setup or by having the same application and expansion connector
Notable are:
– SYM-1 Application and expansion connector, LED and keypad display, tape format
– AIM 65 Application and expansion connector, tape format
– MCS Alpha 1 LED and keypad display, tape format
– Elektor Junior LED and keypad display, tape format
Information on the KIM-1, also reachable from the menu on the right:
On team6502 I found a photo of a prototype KIM-1 at MOS Technology, Terry Holdt has this in his office.
The layout is different from the final product, everything seems to be present on this prototype.
KIM in test frame at a MOS Technology facility (John Feagans)
The 6502 CPU, from MOS Technology, has been widely used since its debut in 1975. Designed by a group of people at MOS Technology led by Chuck Peddle, later of Commodore fame, and used in machines like the PET and C64. Also quickly adapted by computer designers like Steve Wozniak in the Apple series, the 1 and ][ and 2 and 2e and 2c and 3. And many others followed!
The 6502 turned out to be an affordable, yet powerful CPU, easy to interface and easy to understand. Many single board computers were designed with the 6502, most often becoming the heart of largely expanded systems.
The KIM-1, developed by MOS technology as a design example, became such a hit. Many were sold, not only to the original target audience, but also to hobbyists and electronic engineers and system integrators. A new industry was born, based on the microprocessor as the heart of electronic devices. And also the birth of the personal computer, the Apple 2.Nowadays the 6502 is not much more than a memory for most. But the 6502 core is still found in many embedded applications, as sold by the Western Design Centre.
Books in pdf format for download to get started, more books here
The Junior computer design was published by Elektuur/Elektor from 1980 on. It was published in a series of magazine articles, four books and several so called paperware A4 booklets. And the ESS Elektor Software Services for the ROMs.
