Lee Hart's 1802 "Membership Card"

Lee Hart's 1802 "Membership Card"

Last updated Aug 23 2010. Edited by Herb Johnson, (c) Herb Johnson, except for content written by Lee Hart and others. Contact Herb at www.retrotechnology.com, an email address is on that page..

Introduction

This home page is about Lee Hart's "membership card" kits, based on the RCA COSMAC 1802 processor and the early ELF design for that CPU. Currently (Aug 2010) a Rev B kit is in progress, details and prices are below.. A few "Rev A" prototypes were produced in late 2009 and assembled and tested in 2010. The story of the design process and history has been moved to a "development" Web page. This page has links to Web pages about Rev A Membership Card constuction, details of revisions, software include assembler and FORTH, about 1802 history and resources, and other support. Until the "Rev B" product matures, use the "Rev A" resources to learn about the Membership Card and how to assemble and use it.

Here's the assembled Rev A 1802 Membership Card. The Rev A prototypes were constructed by several people: extensive notes and photos were provided by Herb Johnson and P. Todd Decker in 2010. A "Rev B" card was announced in mid-August 2010. Here's a product description and here's the Rev B support Web page.

Todd completed and debugged the kit in May 2010, and provided Lee Hart and myself with discussion about some design issues, resolved in the Rev B version. Todd produced a demonstration video on YouTube in July, titled "COSMAC 1802 Membership Card Checkout" by ptdecker. Photos appear on FLickr titled "1802 Membership Card" by ptdecker. Also, Todd also has a Facebook page as ptdecker.

Another Web page lists revisions and upgrades for the Membership Card with links.
Some software is available on this site for the 1802 and Membership Card.

News, prices, contacts

Current status and prices for the Rev B 1802 Membership card is at this link on this page. The Web page for the Rev B kits is at this Web page. Lee Hart can be contacted by email at This is an image, not an email link.

My home page for my "retrotechnology" activities is at this Web page. Wander from there to my other vintage computing and "retrotechnology" interests. This 1802 project is an example of, and a tribute to, 1970's microcomputing- Herb Johnson

Lee Hart and the history of the "membership card"

A breadboard of the Membership Card circuits. Ode to Eight Bits, by Lee Hart

Here's a summary account of Lee Hart's 1802 work leading to the 1802 Membership Card. See the Membership Card development page for more details.

RCA developed the COSMAC CMOS product line in the mid-1970's, including the 1802 CMOS microprocesor and other support chips. A RCA engineer developed the "Elf", a very small design to program the 1802 with nothing more than toggle switches. In 1982, engineer Lee Hart designed and built an 1802 single board computer called BASYS He also developed a Forth called "8th", a Tiny BASIC, a ROM-only monitor, and other software tools. Meanwhile, variations of Elf-like 1802 products and kits were made throughout the subsequent years. Elf and 1802 products have been discussed for some time in the Yahoo! cosmacelf discussion group, the Cosmac Elf Web site by Dave Ruske, and other Web sites.

In May 2008, I found out that Lee Hart wanted to resurrect his old 1802 FORTH. I found he designed back in 2005-06, some kind of small 1802 product, from discussions in cosmacelf. Lee designed a small-card pair for the 1802 processor which he called the "membership card". It's built to fit inside an Altoids can.

In 2009, Lee was encouraged to pick it up again. He produced a few boards and built a prototype; I established Web pages on my site to support the work, and to capture and make available his prior discussions. The story of that design process and early design history is now on a "Membership Card development" Web page.

With my help and others, he revived his old "8th" language and other software, and he discussed his design process at length. I found a cross assembler in source form and made that available.

In Oct 2009, Lee designed some prototype circuit boards for a small test run. By Nov, Lee produced a handful of circuit boards and distributed these to a few people in cosmacelf. I and others assembled and tested these cards during 2010 and wrote about them. Issues were found with this design, resolved during spring and summer.

Feb 2010: Here's my description of what became the "Rev A" kit, my construction and notes from Lee.

July 2010: P. Todd Decker discovered on his Rev A, a problem with the OUT latch, which is solved by replacing the 74HC373 with a 74HC374. Here's a Web page about his assembling and debugging his kit, including notes for a "single-step" device.

The 2009-10 discussion and Rev A work, is also on the "development" Web page.

Aug 2010: A "Rev B" design and kit is close at hand. here's A Web page on changes from the RevA. A summary of that discussion is is in this text file.

Lee Hart has discussed a second run of several "Rev B" Membership Card boards, in the cosmacelf Yahoo discussion group.

Current status of Membership Card Kits

Lee Hart announces the Rev B kit in cosmacelf. a copy of the announcement and specifications is on this Rev B Web page. Current prices are below.

Lee Hart: "The Rev.B version of my Membership Card is ready for delivery! For those just tuning in, the Membership Card is a reproduction of the original Popular Electronics Elf computer, but shrunk to fit in an Altoids tin! It works the same, and runs the same software."

Aug 20 2010 prices, ordering:

Bare board set: $29 (+ $5 shipping in the US; more for foreign)
Complete kit with parts: $89 (+ $10 shipping in US; more for foreign)

You can order using Paypal to Lee Hart, or mail a check with your order, contact Lee Hart accordingly. - Lee Hart

Lee Hart can be contacted by email at This is an image, not an email link.

Development of the Membership Card

Details of development have been moved to a "development" Web page. The early design process was discussed in the Yahoo! cosmacelf discussion group.. I exerpted Lee Hart's posts at that time (with his permission) edited them into what amounts to his design documents and discussions. - Herb Johnson

Results from Rev A prototypes

a parts list, operating instructions, design discussions
I assembled my rev A Membership Card!
P. Todd Decker tests his Rev A card and finds a flaw..
Testing and using the rev A Membership card
Lee's operating instructions
here's A Web page on changes from the Rev A to Rev B.

Hardware notes

Using the Membership card with a PC parallel port
Low power operation of the Membership Card
The OUT instruction and the Membership card
a single-step circuit for the Membership Card.
Lee Hart's notes on his "Rev A" revisions.
Rev A Revisions and upgrades for the Membership Card

Software

This links to a Web page of the software available for the 1802 and Membership Card. On this Web site, there's a Forth called 8th, a Tiny BASIC, a cross-assembler with course, and a PC parallel port loader in progress.

Software On other sites:

The Cosmac Elf Web site has a Tiny Elf emulator.

Revisions, Availability, Status, Contacts