KIM-1
Encyclopedia
MOS Technology 6502
The MOS Technology 6502 is an 8-bit microprocessor that was designed by Chuck Peddle and Bill Mensch for MOS Technology in 1975. When it was introduced, it was the least expensive full-featured microprocessor on the market by a considerable margin, costing less than one-sixth the price of...
-based single-board computer
Single-board computer
A single-board computer is a complete computer built on a single circuit board, with microprocessor, memory, input/output and other features required of a functional computer. Unlike a typical personal computer, an SBC may not include slots into which accessory cards may be plugged...
developed and produced by MOS Technology, Inc.
MOS Technology
MOS Technology, Inc., also known as CSG , was a semiconductor design and fabrication company based in Norristown, Pennsylvania, in the United States. It is most famous for its 6502 microprocessor, and various designs for Commodore International's range of home computers.-History:MOS Technology, Inc...
and launched in 1976. It was very successful in terms of that period, due to its low price (following from the inexpensive 6502) and easy-access expandability.
History
MOS Technology's first processor, the 6501, could be plugged into existing motherboards that used the Motorola 6800Motorola 6800
The 6800 was an 8-bit microprocessor designed and first manufactured by Motorola in 1974. The MC6800 microprocessor was part of the M6800 Microcomputer System that also included serial and parallel interface ICs, RAM, ROM and other support chips...
, allowing potential users (i.e. engineers and hobbyists) to get a development system up and running very easily using existing hardware. Motorola
Motorola
Motorola, Inc. was an American multinational telecommunications company based in Schaumburg, Illinois, which was eventually divided into two independent public companies, Motorola Mobility and Motorola Solutions on January 4, 2011, after losing $4.3 billion from 2007 to 2009...
immediately sued, forcing MOS to pull the 6501 from the market. Changing the pin layout produced the "lawsuit-friendly" 6502
MOS Technology 6502
The MOS Technology 6502 is an 8-bit microprocessor that was designed by Chuck Peddle and Bill Mensch for MOS Technology in 1975. When it was introduced, it was the least expensive full-featured microprocessor on the market by a considerable margin, costing less than one-sixth the price of...
. Otherwise identical to the 6501, it nevertheless had the disadvantage of having no machine in which new users could quickly start playing with the CPU
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
.
Chuck Peddle
Chuck Peddle
Charles Ingerham Peddle is an American electrical engineer best known as the main designer of the MOS Technology 6502 microprocessor; the KIM-1 SBC; and its successor the Commodore PET personal computer, both based on the 6502....
, leader of the 650x group at MOS (and former member of Motorola's 6800 team), designed the KIM-1 in order to fill this need. The KIM-1 came to market in 1976. While the machine was originally intended to be used by engineers, it quickly found a large audience with hobbyists. A complete system could be constructed for under with the purchase of the kit for only , and then adding a used terminal
Character-oriented terminal
A character-oriented terminal is a type of computer terminal that communicates with its host one character at a time, as opposed to a block-oriented terminal that communicates in blocks of data. It is the most common type of data terminal, because it's easy to implement and program...
and a cassette tape drive
Kansas City standard
The Kansas City Standard , or Byte standard, is a digital data format for audio cassette drives. Byte magazine sponsored a symposium in November 1975 in Kansas City, Missouri to develop a standard for storage of digital computer data on inexpensive consumer quality cassettes, at a time when...
.
Many books were available demonstrating small assembly language
Assembly language
An assembly language is a low-level programming language for computers, microprocessors, microcontrollers, and other programmable devices. It implements a symbolic representation of the machine codes and other constants needed to program a given CPU architecture...
programs for the KIM, including "The First Book of KIM" by Jim Butterfield
Jim Butterfield
-External links:* * featuring Brad Templeton, Jim Butterfield, and Steve Punter** * * , previous unpublished, presented by the Personal Computer Museum, Brantford, Ontario...
et al. One demo program converted the KIM into a music box by toggling a software-controllable output bit connected to a small loudspeaker
Loudspeaker
A loudspeaker is an electroacoustic transducer that produces sound in response to an electrical audio signal input. Non-electrical loudspeakers were developed as accessories to telephone systems, but electronic amplification by vacuum tube made loudspeakers more generally useful...
.
As the system became more popular one of the common additions was the Tiny BASIC programming language
Tiny BASIC
Tiny BASIC is a dialect of the BASIC programming language that can fit into as little as 2 or 3 KB of memory. This small size made it invaluable in the early days of microcomputers , when typical memory size was only 4–8 KB.- History :...
.
This required an easy memory expansion; "all of the decoding for the first 4 K is provided right on the KIM board. All you need to provide is 4 K more of RAM chips and some buffers." The hard part was loading the BASIC from cassette tape—a 15-minute ordeal.
Rockwell International
Rockwell International
Rockwell International was a major American manufacturing conglomerate in the latter half of the 20th century, involved in aircraft, the space industry, both defense-oriented and commercial electronics, automotive and truck components, printing presses, valves and meters, and industrial automation....
—who second-sourced the 6502, along with Synertek
Synertek
Synertek, Inc. was an American semiconductor manufacturer founded in 1973. The initial founding group consisted of Bob Schreiner , Dan Floyd, Zvi Grinfas, Jack Balletto, and Gunnar Wetlesen. The manufacturing technology was MOS/LSI...
—released their own evaluation board in 1976, the AIM 65. The AIM included a full ASCII
ASCII
The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...
keyboard, a 20-character 14-segment alphanumeric
Alphanumeric
Alphanumeric is a combination of alphabetic and numeric characters, and is used to describe the collection of Latin letters and Arabic digits or a text constructed from this collection. There are either 36 or 62 alphanumeric characters. The alphanumeric character set consists of the numbers 0 to...
LED
Light-emitting diode
A light-emitting diode is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting...
display, and a small cash register
Cash register
A cash register or till is a mechanical or electronic device for calculating and recording sales transactions, and an attached cash drawer for storing cash...
-like printer. A debug
Debugger
A debugger or debugging tool is a computer program that is used to test and debug other programs . The code to be examined might alternatively be running on an instruction set simulator , a technique that allows great power in its ability to halt when specific conditions are encountered but which...
monitor
Machine code monitor
A machine code monitor is software built into or separately available for various computers, allowing the user to enter commands to view and change memory locations on the machine, with options to load and save memory contents from/to secondary storage.Machine code monitors became something of a...
was provided as standard firmware
Firmware
In electronic systems and computing, firmware is a term often used to denote the fixed, usually rather small, programs and/or data structures that internally control various electronic devices...
for the AIM, and users could also purchase optional ROM
Read-only memory
Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...
chips with an assembler and a Microsoft BASIC
Microsoft BASIC
Microsoft BASIC was the foundation product of the Microsoft company. It first appeared in 1975 as Altair BASIC, which was the first BASIC, and the first high level programming language available for the MITS Altair 8800 hobbyist microcomputer....
interpreter to choose from.
Finally, there was the Synertek SYM-1
SYM-1
The SYM-1 was a single board "trainer" computer produced by Synertek circa 1978. Originally called the VIM-1 , that name was changed for legal reasons sometime between April and August 1978....
variant, which could be said to be a machine halfway between the KIM and the AIM; it had the KIM's small display, and a simple membrane keyboard
Membrane keyboard
A membrane keyboard is a computer keyboard whose "keys" are not separate, moving parts, as with the majority of other keyboards, but rather are pressure pads that have only outlines and symbols printed on a flat, flexible surface...
of 29 keys (hex digits and control keys only), but provided AIM-standard expansion interfaces and true RS-232
RS-232
In telecommunications, RS-232 is the traditional name for a series of standards for serial binary single-ended data and control signals connecting between a DTE and a DCE . It is commonly used in computer serial ports...
(voltage level as well as current loop mode supported).
Not long after the KIM's introduction, MOS Technology, Inc.
MOS Technology
MOS Technology, Inc., also known as CSG , was a semiconductor design and fabrication company based in Norristown, Pennsylvania, in the United States. It is most famous for its 6502 microprocessor, and various designs for Commodore International's range of home computers.-History:MOS Technology, Inc...
was purchased by Commodore International
Commodore International
Commodore is the commonly used name for Commodore Business Machines , the U.S.-based home computer manufacturer and electronics manufacturer headquartered in West Chester, Pennsylvania, which also housed Commodore's corporate parent company, Commodore International Limited...
and production of the original KIM lasted for a while under the CBM label, before it was ended.
Chuck Peddle started work on an expanded version, with a full built-in QWERTY
QWERTY
QWERTY is the most common modern-day keyboard layout. The name comes from the first six letters appearing in the topleft letter row of the keyboard, read left to right: Q-W-E-R-T-Y. The QWERTY design is based on a layout created for the Sholes and Glidden typewriter and sold to Remington in the...
-keyboard, cassette tape drive, and monochrome monitor display.
The monitor was driven by a new built-in display driver chip, meaning no external terminal was required.
The ROM firmware was expanded to include the BASIC
Commodore BASIC
Commodore BASIC, also known as PET BASIC, is the dialect of the BASIC programming language used in Commodore International's 8-bit home computer line, stretching from the PET of 1977 to the C128 of 1985...
as well, so the machine was up and running as soon as the power was turned on. The result was the Commodore PET
Commodore PET
The Commodore PET was a home/personal computer produced from 1977 by Commodore International...
( RAM, discrete logic graphics), launched in 1977 – one of three historic home/personal computer
Home computer
Home computers were a class of microcomputers entering the market in 1977, and becoming increasingly common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a single nontechnical user...
s to appear that year, the two others being the Apple II (also 6502-based) and the TRS-80
TRS-80
TRS-80 was Tandy Corporation's desktop microcomputer model line, sold through Tandy's Radio Shack stores in the late 1970s and early 1980s. The first units, ordered unseen, were delivered in November 1977, and rolled out to the stores the third week of December. The line won popularity with...
(with a Zilog Z80
Zilog Z80
The Zilog Z80 is an 8-bit microprocessor designed by Zilog and sold from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes...
).
Description
The KIM-1 consisted of a single printed circuit boardPrinted circuit board
A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...
with all the components on one side. It included three main IC
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
s; the MCS6502 CPU, and two MCS6530
MOS Technology RRIOT
The 6530 ROM-RAM-I/O-Timer was an integrated circuit made by MOS Technology, as well as second sources such as Rockwell. It was very similar to the MOS 6532 RIOT, but it incorporated 1 KB of ROM, in addition to the chip's other features. The static RAM, however, was reduced from 128 bytes to 64...
Peripheral Interface/Memory Devices. The MCS6530 "is a mask programmable 1024 x 8 ROM, a 64 x 8 RAM, two 8 bit bi-directional ports …and a programmable interval timer…". The KIM-1 brochure said "1 K BYTE RAM" but it actually had 1152 bytes. The memory was composed of eight 6102 static RAMs(1024 x 1 bits) and the two 64 byte RAMs of the MCS6530s.In the 1970s memory sizes were expressed in several ways. Semiconductor manufactures would use a precise memory size such as 2048 by 8 and sometimes state the number of bits (16384). Mini and mainframe computers had various memory widths (8 bits to over 36 bits) so manufactures would use the term "words", such as 4K words. The early hobbyist computer advertisements would use both "words" and "bytes". It was common to see "4096 words", "4K (4096) words" and "4 K bytes". The term KB was unused or very uncommon. The KIM-1 was introduced in the April 1976 issue of Byte magazine and the advertisement stated "1 K BYTE RAM" and "2048 ROM BYTES".
Also included were six 7-segment
Seven-segment display
A seven-segment display , or seven-segment indicator, is a form of electronic display device for displaying decimal numerals that is an alternative to the more complex dot-matrix displays...
LED
Light-emitting diode
A light-emitting diode is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting...
s (similar to those on a pocket calculator
Calculator
An electronic calculator is a small, portable, usually inexpensive electronic device used to perform the basic operations of arithmetic. Modern calculators are more portable than most computers, though most PDAs are comparable in size to handheld calculators.The first solid-state electronic...
) and a 24-key calculator-type keypad.
Many of the pins of the I/O portions of the 6530s were connected to two connectors on the edge of the board, where they could be used as a serial
Serial communications
In telecommunication and computer science, serial communication is the process of sending data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits are sent as a whole, on a link with several parallel channels...
system for driving a Teletype
Teletype Corporation
The Teletype Corporation, a part of American Telephone and Telegraph Company's Western Electric manufacturing arm since 1930, came into being in 1928 when the Morkrum-Kleinschmidt Company changed its name to the name of its trademark equipment...
Model 33 ASR and paper tape reader/punch).
One of these connectors also doubled as the power supply connector, and included analog lines that could be attached to a cassette tape recorder.
Earlier microcomputer
Microcomputer
A microcomputer is a computer with a microprocessor as its central processing unit. They are physically small compared to mainframe and minicomputers...
systems such as the MITS Altair
Altair 8800
The MITS Altair 8800 was a microcomputer design from 1975 based on the Intel 8080 CPU and sold by mail order through advertisements in Popular Electronics, Radio-Electronics and other hobbyist magazines. The designers hoped to sell only a few hundred build-it-yourself kits to hobbyists, and were...
used a series of switches on the front of the machine to enter data. In order to do anything useful, the user had to enter a small program known as the "bootstrap loader" into the machine using these switches, a process known as booting
Booting
In computing, booting is a process that begins when a user turns on a computer system and prepares the computer to perform its normal operations. On modern computers, this typically involves loading and starting an operating system. The boot sequence is the initial set of operations that the...
. Once loaded, the loader would be used to load a larger program off a storage device like a paper tape reader. It would often take upwards of five minutes to load the tiny program into memory, and a single error while flipping the switches meant that the bootstrap loader would crash the machine. This could render some of the bootstrap code garbled, in which case the programmer had to reenter the whole thing and start all over again.
The KIM-1 included a somewhat more complex built-in Terminal Interface Monitor software called TIM that was "contained in 2048 bytes of ROM in two 6530 ROM/RAM/IO arrays". This monitor software included the ability to run a cassette tape for storage, drive the LED display, and run the keypad. As soon as the power was turned on, the monitor would run and the user could immediately start interacting with the machine via the keypad. The KIM-1 was one of the first single-board computer
Single-board computer
A single-board computer is a complete computer built on a single circuit board, with microprocessor, memory, input/output and other features required of a functional computer. Unlike a typical personal computer, an SBC may not include slots into which accessory cards may be plugged...
s, needing only an external power supply to enable its use as a stand-alone experimental computer. This fact, plus the relatively low cost of getting started, made it quite popular with hobbyists through the late 1970s.
Video display
The designer of the TV TypewriterTV Typewriter
The TV Typewriter was a video terminal that could display 2 pages of 16 lines of 32 upper case characters on a standard television set. The Don Lancaster design appeared on the cover of Radio-Electronics magazine in September 1973. The magazine included a 6 page description of the design but...
, Don Lancaster
Don Lancaster
Donald E. Lancaster is a prolific author, inventor, and microcomputer pioneer best known for his magazine columns. He is also known for his "TV Typewriter" dumb terminal project, his book on technical entrepreneurship The Incredible Secret Money Machine, and his work on and advocacy of early...
, developed a low cost video display for the KIM-1. The add-on board would display up to 4000 characters on a TV or monitor. A typical configuration would be 16 lines of 32 upper case only characters. The board had only 10 low cost ICs and used the KIM's memory for the screen storage.
The TVT-6 project appeared on the cover on Popular Electronics
Popular Electronics
Popular Electronics was an American magazine started by Ziff-Davis Publishing in October 1954 for electronics hobbyists and experimenters. It soon became the "World's Largest-Selling Electronics Magazine". The circulation was 240,151 in April 1957 and 400,000 by 1963. Ziff-Davis published Popular...
in July 1977. The complete kit could be ordered from PAiA Electronics
PAiA Electronics
PAiA Electronics, Inc. is an American synthesizer kit company that was started by John Simonton in 1967. It sells various musical electronics kits including analog synthesizers, theremins, mixers and various music production units designed by founder John Simonton, Craig Anderton, Marvin Jones,...
for .
Don expanded this design to do color and simple graphics in The Cheap Video Cookbook.
Specifications
- CPU: MCS6502MOS Technology 6502The MOS Technology 6502 is an 8-bit microprocessor that was designed by Chuck Peddle and Bill Mensch for MOS Technology in 1975. When it was introduced, it was the least expensive full-featured microprocessor on the market by a considerable margin, costing less than one-sixth the price of...
- 2x PIO MCS6530MOS Technology RRIOTThe 6530 ROM-RAM-I/O-Timer was an integrated circuit made by MOS Technology, as well as second sources such as Rockwell. It was very similar to the MOS 6532 RIOT, but it incorporated 1 KB of ROM, in addition to the chip's other features. The static RAM, however, was reduced from 128 bytes to 64...
, a , 2x 8-bit bi-directional ports, programmable interval timerProgrammable Interval TimerIn computing and in embedded systems, a programmable interval timer is a counter which triggers an interrupt when it reaches the programmed count.- Common features :... - 8x 6102 static RAMStatic random access memoryStatic random-access memory is a type of semiconductor memory where the word static indicates that, unlike dynamic RAM , it does not need to be periodically refreshed, as SRAM uses bistable latching circuitry to store each bit...
1024 x 1 (1152 bytes) - 6x 7-segmentSeven-segment displayA seven-segment display , or seven-segment indicator, is a form of electronic display device for displaying decimal numerals that is an alternative to the more complex dot-matrix displays...
LEDLight-emitting diodeA light-emitting diode is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting...
s - 24-key calculator type keypadKeypadA keypad is a set of buttons arranged in a block or "pad" which usually bear digits, symbols and usually a complete set of alphabetical letters. If it mostly contains numbers then it can also be called a numeric keypad...
- 2x serialSerial communicationsIn telecommunication and computer science, serial communication is the process of sending data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits are sent as a whole, on a link with several parallel channels...
ports - Terminal Interface Monitor (TIM), that handled bootingBootingIn computing, booting is a process that begins when a user turns on a computer system and prepares the computer to perform its normal operations. On modern computers, this typically involves loading and starting an operating system. The boot sequence is the initial set of operations that the...
, keypad, 7-seg LEDs, and cassette tape
Tape format
Each bit is represented by three 2.484 ms long tones. The first is always 3700 Hz, the middle is 3700 Hz for "0" or 2400 Hz for "1", and the last one is always 2400 Hz. This gives an effective bit rate of 134.2 bit/s. Detection is done through a PLLPhase-locked loop
A phase-locked loop or phase lock loop is a control system that generates an output signal whose phase is related to the phase of an input "reference" signal. It is an electronic circuit consisting of a variable frequency oscillator and a phase detector...
using LM565.
The format of data on the tape is: 100 bytes with the value 0x16 (SYN, Synchronous Idle), one byte with the value 0x2A (*), the record identification number, the start address (two characters for the low byte of address, two characters for the high byte), the end address (in the same format), the actual data, one byte with the value 0x2F ("/" character ), a two-byte checksum
Checksum
A checksum or hash sum is a fixed-size datum computed from an arbitrary block of digital data for the purpose of detecting accidental errors that may have been introduced during its transmission or storage. The integrity of the data can be checked at any later time by recomputing the checksum and...
, and two bytes with the value 0x04 (EOT, End Of Transmission).
Each byte of memory is stored as two sequential ASCII characters on tape, for example, hexadecimal
Hexadecimal
In mathematics and computer science, hexadecimal is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0–9 to represent values zero to nine, and A, B, C, D, E, F to represent values ten to fifteen...
B5 in memory (181 decimal) would be stored as two sequential ASCII characters "B" and "5" (42 and 35 hexadecimal).
See also
- Microprocessor development boardMicroprocessor development boardA microprocessor development board is a printed circuit board containing a microprocessor and the minimal support logic needed for an engineer to become acquainted with the microprocessor on the board, and to learn to program it...
- Elektor Junior ComputerElektor Junior ComputerThe Elektor Junior Computer was a simple 6502 based microprocessor development board published in the 1980s in the Dutch, German and later French, Spanish and British versions of Elektor/Elektuur, in the form of a series of articles, and four books...
- AIM-65AIM-65The Rockwell AIM-65 computer was a development computer based on the MOS Technology 6502 microprocessor introduced in 1976. The AIM-65 was essentially an expanded KIM-1 computer. Available software included a monitor with line at a time assembler/disassembler, BASIC interpreter, assembler, Pascal,...
- SYM-1SYM-1The SYM-1 was a single board "trainer" computer produced by Synertek circa 1978. Originally called the VIM-1 , that name was changed for legal reasons sometime between April and August 1978....
External links
- The KIM-1 exhibit at the virtual computer museum OLD-COMPUTERS.COM
- KIM-1 and collection of old digital and analog computers at oldcomputermuseum.com
- KIM-1 6502 website – erik.vdbroeck's resource site for the KIM-1, with several HTMLHTMLHyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....
'ized manuals and books - Instructions on building your own KIM-1
- KIM-1 Hints/FAQ
- Floodgap Retrobits KIM-1 with archival links and an emulatorEmulatorIn computing, an emulator is hardware or software or both that duplicates the functions of a first computer system in a different second computer system, so that the behavior of the second system closely resembles the behavior of the first system...
that runs on the Commodore 64Commodore 64The Commodore 64 is an 8-bit home computer introduced by Commodore International in January 1982.Volume production started in the spring of 1982, with machines being released on to the market in August at a price of US$595... - Modern KIM-1 clone website
- KIM-1 hobbyist's development: pictures of KIM-1, and of its clone.