The KIM -1 (Keyboard Input Monitor ) was one of the first home computers based on the 6502 CPU and was designed by MOS Technology, Inc., later acquired by Commodore, developed in 1976.
The KIM -1 consisted of a single-board computer, which contained all the necessary integrated circuits on a printed circuit board: The 6502, two 6530 multi-function blocks ( each with 1 KB ROM, 64 bytes of RAM and multiple I / O channels ) and 1 KB regular RAM. Overall, the KIM -1, therefore, had a capacity of 1152 bytes of RAM and 2048 bytes ROM. The clock frequency of 6502 microprocessor was 1 MHz. Similarly, the KIM- 1 contained a six-digit 7-segment LED display and offered 24 keys for direct entry of HEX code. Several of the I / O ports could be used for serial communication, or for connecting an external terminal or printer (TTY 20mA loop) as well as a cassette interface. An expansion port that provides all data, address and clock signals is also provided. This allows the extension to a system with more memory or other peripheral devices.
The MCS Alpha 1 was copied as a clone of the KIM -1 and received a housing with its own power supply and had some additional improvements. The memory was still limited to 1 KB RAM. Instead of 6 LEDs used the MCS Alpha 8 and could be easily operated using a monitor program. In addition to the CPU of the computer contained two chips 6532 and EPROM, a keyboard, a serial interface, and a cartridge.
The KIM -1 was characterized by a relatively complex BIOS. This " monitor " programs is called TIM (Terminal Input Monitor ) and KIM (Keyboard Input Monitor ) and were housed in the two 1 -KB ROM chips 6530. This monitor software made it possible to connect a cassette recorder as an external storage medium to control the LED display and query the keyboard.
Once the KIM-1 was turned on, the monitor and the user was able to operate the device directly via keystrokes. Thus, the KIM -1 was one of the first single-board computer, which only require an external power supply for operation. This fact and the fact that he allowed a low -cost alternative to entry into the then computer technology, made him very popular with many amateur programmers of the 1970s.
The Microsoft BASIC programming language was first released for the KIM -1.
The developer of the TV Typewriter, Don Lancaster, developed an inexpensive screen display for the KIM -1. The additional circuit board set up to 4000 characters on a TV or monitor represents a typical representation could produce 16 lines of 32 characters each in uppercase. The board was only equipped with ten -cost ICs and used the KIM -1 as a storage for screen display.