Daves Old Computers - Commodore/MOS KIM-1

In 1975, MOS Technology designed a small computer to showcase their new 6502 processor. This was released in 1976 as the KIM-1 (Keyboard Input Monitor).

The KIM-1 is a very simple computer. It consists of a 6502 processor, with two 6530 multi-purpose chips, each of which contains 1024 bytes of ROM, 64 bytes of RAM, a timer and 15 I/O pins. 8 1kx1 static RAMs add another 1K bytes of memory, and a handful of logic interfaces a keypad, LED display, bit-banged TTY port and a cassette tape interface. Within the 2K of ROM is a control program which provides basic monitor functions via the keypad and display. Two 44-pin expansion connectors allow the KIM-1 to grow.

Click any photo to view a large high-resolution image.

Later that year, MOS was acquired as Commodore International, a calculator company who wanted to step up into the microcomputer business. Their first computer system was the MOS KIM-1, now bearing both the Commodore and MOS logos.

The KIM-1 was delivered as an assembled and tested board. You provided the case (if any) and power supply.

Here is a view of the back. The rubber feet were supplied with the unit.

The KIM-1 user manual that I have is an original MOS one. The MOS and Commdore verions are identical save for the change in logo, color of the board, and the position of the single-step switch. The "First book of Kim" shows the MOS version on it's cover.

KIM Hints Manual(2.1M PDF)
KIM Monitor Source Listing(35k ASM)

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Copyright 2004-2005 Dave Dunfield.