Lee Hart's BASYS card design

This Web page discusses the COSMAC 1802-based BASYS card designed by Lee Hart in 1982. This note Last updated Sept 22 2014. Edited by Herb Johnson, (c) Herb Johnson



In the mid-1970's the RCA Laboratory in central New Jersey, now called the David Sarnoff Center, developed a line of CMOS integrated circuit chips, branded COSMOS. This led to an early microprocessor line around the 1802, RCA's CMOS microprocessor. The designer produced an 1802 kit which was simple enough to be built by hobbyists - a common practice in the era - called the ELF. Many generations of ELF computers were subsequently built, redesigned and sold, from the 1970's to the present day (2012).

Lee Hart built an ELF himself in the era. In 1978, years after seeing a RCA MicroTutor and MicroKit, Lee Hart designed and built for TMSI, a COSMAC 1802 based single board computer called BASYS. A photo is to the left on this Web page. It ran on almost no power - the serial line interface current could power the whole computer! Here's a photo of the serial interface module. This Web page discusses the BASYS product, some uses of it, its technology, and its successors.

BASYS and other work, led Lee Hart to a series of 1802 projects which he discusses in the linked document. In 2006, he prototyped a kind of "successor" to the BASIS and to the ELF, the "membership card". In 2009, he first offered a Membership Card kit; as of 2012 it's in third revision and available on the linked Web page. - Herb Johnson

BASYS docs and software

Here's a TIF/PDF scan of my BASYS manual, permitted by Lee Hart/TMSI. Also, here's notes in the Tiny BASIC manual that I've abstracted for a brief hardware view of the BASYS. Here'sa higher-quality JPEG of the board schematic and of the interface schematic.

Lee Hart wrote a ROM monitor for the 1802, called "IDIOT", in 1982 for his BASYS product.

Lee obtained a Tiny BASIC from Tom Pittman and wrote a version for the 1802. The manual includes hardware information about the BASYS.

Another Lee Hart software tool for the 1802 was his 1802 version of Forth, which he called "8th". If you check that Web page, the ZIP file of 8th code includes the version 1.2 ROM image from my BASYS board. Here's a closer image of my BASYS board jumper areas.

Successors to BASYS

Lee said: "My first 1802 robot was Itsabox (It's A Box turtle robot; get it?) It was a BASYS board driving two stepper motors for the left and right wheels, two toe switches to sense the edges of the table, and two finger switches to sense when it touched an object. There was also an RS-232 port, and a speaker to make noises. It was programmed in 8TH, and worked like the Logo turtle robots."

Another version of the BASYS was mounted in a box, with a solderless breadboard on top; This was called Proteus, as in "prototypes".

Lee compared 1802 products like BASYS and another of his designs called PROTEUS, to modern microcontrollers like the Microchip PIC, in another discussion.

That discussion and others led Lee to the design of a new 1802 product in 2009. It's another 1802 card called the COSMAC 1802 Membership Card. That linked Web page will have links to the current version of the card, previous versions, software and hardware resources, and development history.

BASYS owners today

Rod Kapela wrote to me and Lee Hart in 2012:

I used one of those computers to make my own robot back in 1983. [It has the form of a flower, and the computer is is in the pot or base.]

This flower was supposed to wait till there was enough light, then it would open it's petals then scan until it found the brightest spot. The antlers were four photodiodes, which controlled a motor to rotate around in the pot and a motor to move up and down. The flower and the leaves holds 11 three-inch solar cells which should be enough to charge 4 NiCad batteries.

The flower would track the sun until the batteries were recharged then would try making 'music' with 1 one bit digital to analog converter.

I've started to fix it up, but I no longer have the software that I wrote to run it. It was written in 8th, which does not seem to be documented anywhere. [I referred him to the 8th docs on this site - Herb]

I need to buy or make a USB to RS-232 converter to talk to the board, it's been a while since I had a serial port on a computer. Do you know the default speed of the serial port on the board? - Rod

Other owners of BASYS

Steward Marshall's BASYS boards are boxed by Steward, and shown on the ELF owner's show-and-tell Web section of cosmacelf.com. Look on the site for many other 1802 resources and history.

another BASYS owner describes his, in a blog entry on an Atari support Web site.

Other Web links

another archive of Lee's Hart's BASYS work on cosmacelf.com, including Tiny BASIC, is part of cosmacelf's software archives. There's a Yahoo disscussion group "cosmacelf" as well.

Note: A collection of the Sarnoff's RCA artifacts was maintained for many years at that site, it is now elsewhere. See the Web link about Sarnoff's former collection for details.

Contact information for Herb Johnson:
Herb Johnson
New Jersey, USA
To email @ me, see
see my home Web page.

This page and edited content is copyright Herb Johnson (c) 2012. Contact Herb at www.retrotechnology.com, an email address is available on that page..