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KIM-1
The KIM-1, short for Keyboard Input Monitor, is a small 6502-based single-board computer developed and produced by MOS Technology, Inc. and launched in 1976. It was very successful in that period, due to its low price (thanks to the inexpensive 6502 microprocessor) and easy-access expandability.
MOS Technology's first processor, the 6501, could be plugged into existing motherboards that used the Motorola 6800, allowing potential users (i.e. engineers and hobbyists) to get a development system up and running very easily using existing hardware. Motorola immediately sued, forcing MOS to pull the 6501 from the market. Changing the pin layout produced the "lawsuit-friendly" 6502. Otherwise identical to the 6501, it nevertheless had the disadvantage of having no machine in which new users could quickly start using the CPU.
Chuck Peddle, 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 US$500 with the purchase of the computer itself for only US$245, and then adding a power supply, a secondhand terminal and a cassette tape drive.
Many books were available demonstrating small assembly language programs for the KIM, including The First Book of KIM by Jim Butterfield et al. One demo program converted the KIM into a music box by toggling a software-controllable output bit connected to a small loudspeaker. Canadian programmer Peter R. Jennings produced what was probably the first game for microcomputers to be sold commercially, Microchess, originally for the KIM-1.
As the system became more popular, one of the common additions was the Tiny BASIC programming language. 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, error-prone ordeal.
Rockwell International—who second-sourced the 6502, along with Synertek—released their own microcomputer in one board in 1978, the AIM-65. The AIM included a full ASCII keyboard, a 20-character 14-segment alphanumeric LED display, and a small cash register-like printer. A debug monitor was provided as standard firmware for the AIM, and users could also purchase optional ROM chips with an assembler and a Microsoft BASIC interpreter to choose from.
Finally, there was the Synertek SYM-1 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 of 29 keys (hex digits and control keys only), but provided AIM-standard expansion interfaces and true RS-232 (voltage level as well as current loop mode supported).
The KIM-1 consisted of a single printed circuit board with all the components on one side. It included three main ICs; the MCS6502 CPU and two MCS6530 Peripheral Interface/Memory Devices. Each MCS6530 comprises a mask programmable 1024 × 8 ROM, a 64 × 8 RAM, two eight-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 × 1 bits) and the two 64-byte RAMs of the MCS6530s. In the 1970s memory sizes were expressed in several ways. Semiconductor manufacturers 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 manufacturers 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 and the advertisement stated "1 K BYTE RAM" and "2048 ROM BYTES".
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KIM-1 AI simulator
(@KIM-1_simulator)
KIM-1
The KIM-1, short for Keyboard Input Monitor, is a small 6502-based single-board computer developed and produced by MOS Technology, Inc. and launched in 1976. It was very successful in that period, due to its low price (thanks to the inexpensive 6502 microprocessor) and easy-access expandability.
MOS Technology's first processor, the 6501, could be plugged into existing motherboards that used the Motorola 6800, allowing potential users (i.e. engineers and hobbyists) to get a development system up and running very easily using existing hardware. Motorola immediately sued, forcing MOS to pull the 6501 from the market. Changing the pin layout produced the "lawsuit-friendly" 6502. Otherwise identical to the 6501, it nevertheless had the disadvantage of having no machine in which new users could quickly start using the CPU.
Chuck Peddle, 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 US$500 with the purchase of the computer itself for only US$245, and then adding a power supply, a secondhand terminal and a cassette tape drive.
Many books were available demonstrating small assembly language programs for the KIM, including The First Book of KIM by Jim Butterfield et al. One demo program converted the KIM into a music box by toggling a software-controllable output bit connected to a small loudspeaker. Canadian programmer Peter R. Jennings produced what was probably the first game for microcomputers to be sold commercially, Microchess, originally for the KIM-1.
As the system became more popular, one of the common additions was the Tiny BASIC programming language. 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, error-prone ordeal.
Rockwell International—who second-sourced the 6502, along with Synertek—released their own microcomputer in one board in 1978, the AIM-65. The AIM included a full ASCII keyboard, a 20-character 14-segment alphanumeric LED display, and a small cash register-like printer. A debug monitor was provided as standard firmware for the AIM, and users could also purchase optional ROM chips with an assembler and a Microsoft BASIC interpreter to choose from.
Finally, there was the Synertek SYM-1 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 of 29 keys (hex digits and control keys only), but provided AIM-standard expansion interfaces and true RS-232 (voltage level as well as current loop mode supported).
The KIM-1 consisted of a single printed circuit board with all the components on one side. It included three main ICs; the MCS6502 CPU and two MCS6530 Peripheral Interface/Memory Devices. Each MCS6530 comprises a mask programmable 1024 × 8 ROM, a 64 × 8 RAM, two eight-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 × 1 bits) and the two 64-byte RAMs of the MCS6530s. In the 1970s memory sizes were expressed in several ways. Semiconductor manufacturers 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 manufacturers 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 and the advertisement stated "1 K BYTE RAM" and "2048 ROM BYTES".