COSMAC VIP

The COSMAC VIP (1977) was an early microcomputer that was aimed at video games. For a price of US$275, it could be purchased from RCA by mail order. It came in kit form, and had to be assembled. Its dimensions were 8.5 by 11 inches, and it had a RCA 1802 processor; along with a crystal clock operating at 1.76MHz (3.521280MHz divided by 2). It had 2 KB (2,048 bytes) of RAM, which could be expanded to 4K on-board, and 32 KB via an expansion slot. Its 5V DC CDP18S023 power supply had an output of 600 mA. I/O ports could be added to connect to sensors, interface relays, an ASCII keyboard, or a printer.

The machine connected to a TV for video output (using a CDP1861/CDP1864 video display chip), and sound could be played using its integrated speaker. It had a 100 bytes per second cassette tape interface as well. Programs could be loaded into RAM from tapes, and vice versa. It also had a hex keyboard for input, which had 16 keys spanning the hex digits 0 to F. LED indicators were used to display power status and tape input; a third LED along with an on-board beeper were activated by the CPU's 1-bit "Q" register. A run/reset switch was used to start user programs or the operating system, respectively.

A simple 4-kilobit (512-byte) operating system was built into its ROM. It allowed one to type in programs using its hex keyboard, show memory contents on its display (step through the bytes of RAM), and view the values of the processor registers. The ROM monitor was accessed by holding the "C" key while switching from Reset to Run. The COSMAC VIP was shipped with 20 video games, which were programmed in CHIP-8. CHIP-8 was an early interpreted programming language that was used on this machine and other early microcomputers, such as the Telmac 1800.

References

*The December 1978 BYTE magazine featured an article on CHIP-8 ("An Easy Programming System") as well as an advertisement for the VIP system.
*The May 1977 Dr. Dobb's Journal reprinted an article by Joseph Weisbecker of RCA Laboratories ("A Practical, Low-cost, Home/School Microprocessor System") describing the design philosophies and economies that went into designing the VIP -- which was at the time called FRED ("Flexible Recreational and Educational Device"). That article originally appeared in the August 1974 IEEE "Computer" magazine.

External links

* [http://www.old-computers.com/museum/doc.asp?c=543 old-computers.com article: Cosmac VIP]
* [http://www.vintagecomputermusic.com/ Recordings of Cosmac VIP playing music]
* [http://groups.yahoo.com/group/rcacosmac RCA COSMAC Yahoo! Group]