Lee Hart's 1802 "Membership Card"

Last updated apr 23 2024. Edited by Herb Johnson, (c) Herb Johnson, with content written by myself, Lee Hart and others.

[assembled kit]

[rev L Front Panel]

This is the home page for Lee Hart's 1802 Membership Card kits, based on the RCA COSMAC 1802 processor and the early ELF microcomputer design with that CPU. "For those just tuning in, the Membership Card is a reproduction of the original Popular Electronics COSMAC 1802 Elf computer, but shrunk to fit in an Altoids tin! It works the same, and runs the same software." - Lee Hart, developer. There's toggle switches and LEDs for 1970's binary programming - no other hardware needed. Current versions have options for ROM and RAM, hex displays, serial hardware interfaces, 8-bit hardware interfaces. A single-card kit is available, or the full kit with CPU board plus front-panel board of LEDs and switches. It can be operated without any other computer from the front panel.. Or you can make a serial connection and run with a ROM monitor or BASIC interpreter; ROMs and binaries are available. It runs for days on small batteries or even on solar cells, with low-power CMOS components including the CPU.

What is this kit?

[unassembled kit]

The description and support Web page for the current Rev L1 CPU with Rev L Front Panel, is at this Web link. Rev L front panel was in distribution since May 4 2022; Rev L1 CPU since Mar 5 2024. The previous Rev L CPU and L Front panel, was in distribution since July 1 2022. The previous Rev K4 CPU and L Front panel was in distribution before July 1 2022. For detailed information on these and earlier versions, check the Production Version section at the bottom of this Web page.

The 1802 Membership Card full kit, provides a complete COSMAC 1802 computer you can build and program, without use of any other computer! Just like the original series of "COSMAC Elf"s. Or, assemble the CPU board only with a ROM monitor, and run it from a serial connection. With a ROM monitor and a serial connection to a computer USB or serial port, you can do more. The front-panel card permits manual operation and provides hardware bits in and out.

This Web page provides summary information, with links to many other Web page resources on this site, to results from 1802 M/S card owners, and more. Every version of the 1802 MC is covered.

Major changes for the 1802 Membership Card

July 2022: jump on reset. The new Rev L CPU supports a jump-on-reset feature. Hold the IN button while toggling the RESET switch, and the 1802 will briefly execute code from the "HI" jumpered ROM (or RAM) at 8000H instead of the "LO" jumpered ROM or RAM at 0000H. Then high and low memory are restored. This supports low-RAM / high-ROM operations.

May 2022: front panel numeric display. The new Rev L front Panel supports two or six 7-segment LEDs, with a ROM to display hex or ASCII characters. The two central segment displays, show the hex value on the output port, no software needed. To display six digits of values or characters, additional software is needed including an interrupt handler. The interrupt and a timer flag are generated by a hardware timer on the front-panel. Access to the 30 pin signals, formerly provided by a DB-25 connector, is still available by adding a second 30-pin header to the Rev L front-panel board.

Details are provided on the Web pages supporting these Rev L boards, and in the manuals provided with those kits.

HOW TO ORDER kits and most-current software, documents, support

[empty boards]

HOW TO ORDER: Purchase direct from Lee Hart on his Membership Card ordering Web page at this link. Products, descriptions, manuals, prices and Paypal terms are on that page.

[empty boards]

Available: Bare Logic Boards (Membership Card and Front Panel), with schematic and construction manual;
OR A Kit of Bare Logic Boards as above plus all components - manual online;
OR A Kit as above plus Front Panel Cover board;
AND a protoboard for custom interfaces. Here's details about the protoboard.
AND you can buy ROMS with BASIC and/or a monitor program - details and manuals on the ordering Web page
ALSO There's a Clock kit front-panel, described on the Lee Hart's ordering Web page.

"Wow! This kit is too much for me! Consider Lee Hart's 1802 MemberChip kit. Check the linked Web page for a smaller but challenging 1802 kit.

AGAIN: Purchase direct from Lee Hart on his Membership Card ordering Web page at this link.

The complete kits come with parts and boards and build instructions in a classic *paper* manual! Or, you can buy the boards, and use those manuals to buy the parts yourself (but the kit is cheaper).

Why is this a quality kit for the beginner or vintage builder?

[edge view]

Small size, ordinary components, assembly manual for hands-on building. The front panel and CPU boards stack to fit in an Altoids tin. (Rev I stack shown.) The front panel cover board (optional) fits over the Altoids lid.

Only readily-available electronic parts are used (except the 1802) and are part of the kit. Most parts are from the 1970's "ELF" era. All thru-hole parts (not surface mount), for easy hand assembly. Assembly manual guides construction, part by part, with testing and debug information.

Quality printed-circuit board, easy to see, build and repair:
- quality PC board material, 1 oz. copper, 15 mil wide traces
- white, legible "silk screen" text to identify parts
- 60 mil large pads, 40 mil holes to fit larger pins or pin-socket inserts
- large holes and pads are easier to desolder misplaced parts without damage
- gives a 70's look to a 1976 processor kit

"On occasion, customers have put parts in the wrong places. They commented [to me] that they were amazed they could remove them without damaging the PCB." - Lee Hart June 2021

What's on THIS Web site for the 1802 Membership Card?

This Web page has links to notes on hardware, links to software including an assembler, BASIC, FORTH and ROM monitors; about 1802 history and resources. There's a summary history of the Membership card development and revisions, including links to previous versions' Web pages here. Also, links to other people's builds and software for the Membership Card; and links to other 1802 resources. Finally, this page has recent news about the 1802 Membership Card.

HOW TO ORDER, status, contact, support
Hardware and interface notes
Software notes and links
Modern microcontrollers, other people's builds, for the Membership Card
1802 M/S card news, events
Current and out of production versions
A summary history of the Membership card
Development of the COSMAC 1802, ELF, and the "Membership Card"
other 1802 resources

For comments and corrections of content on this and other Membership Card pages, contact Herb at www.retrotechnology.com, an email address is on that page..

Production and Support:

Links to the current 1802 support page is at the top of this Web page. To order, see the link to Lee Hart's sales page. Information and support about previous versions is linked below. To see some Membership Card builds and software, see the "other people's builds" section. More information is linked from this Web page. There's many other Web pages on this site for the 1802 MC and the COSMAC; try a Web search and add the phrase "site:retrotechnology.com".


ROM monitor, BASIC: Binaries of a ROM monitor and BASIC (or actual ROMs) are available from the 1802 M/S Card sales Web site. Here's operation of the Rev J M/S card with BASIC 3 and an FTDI-chipped USB serial adapter.

Also: If you want an old-skool ROM monitor, RAM and a serial connector: Parts, serial connectors, IDIOT monitor ROM and RAM, is described on this linked Web page. There's other 1802 ROM monitors and programs on this Web site, and other Web sites. See the software notes below for details.

How do I load and run a program? Here's a Web page on how to operate the Membership card. There's example programs, too.

Recent news: See the News section for more details on recent and earlier events. The 1802 M/S card has been sold at various vintage computing events. It's described on various Web pages, blogs and discussion groups. A gallery of 1802 Membership Cards is shown on the cosmacelf.com Web site.

Who are these people?

Lee Hart designs, works on and discusses electric cars and designs EV electronics as products and for construction by individuals. He worked with microprocessors from their 8-bit beginnings, and has a series of Altoid-sized kits for them. Check my links on my Membership Card ordering section to contact Lee about buying the 1802 Membership Card.

Herb Johnson is the producer/editor of this collection support Web pages and owner of this Web domain "retrotechnology.com". Contact me at my home page. Follow the links there, or use Web search (keywords followed by "site:retrotechnology.com") to find my other vintage computing and "retrotechnology" interests. This 1802 project is an example of, and a tribute to, the 1970's microcomputing era I'm trying to preserve and support. Learn on my site, about 1970's vintage computer repairs and history. - Herb Johnson

What is this kit about?

See the top of this Web page. ;)

Other people's builds, software, hardware for the Membership Card

The 1802 Membership Card will be ELEVEN years in production by late 2021; many people have bought and built it. Some of them have interesting builds, or documented their work. Others have added modern hardware - microcontrollers like Arduino or Raspberry Pi. Here's some noteworthy "builds" with connections to modern hardware and software. Web search for "1802 Membership Card" will find more.

Hardware and interface notes

Here's a link to notes about testing and operating your 1802 M/S card. It discusses how to operate the Membership card from the front panel, and provides test programs.

See the Membership Card hardware Web page, for a list and links to documents about the hardwareof the 1802 Membership card. Among those notes are use of a PC parallel port and the M/S card's DB-25; adding ROM and RAM together and a serial port; serial, parallel or USB loaders; low power operation; single-step operation; various ways to upgrade the M/S card (discussed below); stacking M/S card CPU boards to double RAM, ROM and I/O; and some undocumented 1802 states between LOAD and CLEAR.

How to expand the 1802 M/S Card hardware & software

Some history: The 1802 Membership Card kit will be 12 years in production as of Oct 2022. Yet it's based on the Popular Electronics magazine "COSMAC Elf" from 1976 which preceeded many personal computers. IN that era, the Elf had to be simple. Very few people in 1976 had computers, or keyboards, or anything "digital" - so the ELF operated from lights and switches in binary. The 1802 Membership Card is a direct descendant of the COSMAC ELF. Both have a simple byte-wide set of lights and switches, to load and run programs directly to and from memory - like the ELF. Lee Hart's Membership Card also has a "PC parallel port interface", to operate the M/S card with that old "PC standard". And, that M/S Card binary interface can operate external devices, or those devices can operate the M/S card. And there's a serial interface too, but it needs software to operate, and modern USB-to-serial hardware to connect to a computer's USB port as a serial device like a terminal. This section discusses all these "modern" options for the vintage 1802 Membership Card.

RAM and ROM options: Recent versions accept a narrow-width RAM chip, to mount under the wide ROM chip so a ROM monitor or other programs can operate with RAM. Basic instructions to set these up, are in the kit assembly manual. A more general and technically detailed discussion of the serial interface and operation of a ROM monitor is on this linked Web page.

Serial options:Current versions of the 1802 MC accomdate a TTL-to-USB adapter to both power the board and to serial communicate with a ROM monitor. Previous versions have circuits on the Front Panel board to provide TTL or RS-232 "serial" input and output interfaces. These use the Q and EF3 bits from the 1802, and a "bit-bang" or software UART, to manage ASCII serial data. An 1802 monitor or BASIC programs, can provide a software UART and operating commands. Recent versions have a power/serial connector for convenient connection to a TTL-to-USB adapter; or one can add a RS-232 like serial interface. A kit of serial connectors, IDIOT monitor ROM, and narrow RAM, is described on this linked Web page. The sales Web page includes ROM codes for a monitor and BASIC.

Here's operation of the Rev J M/S card with BASIC 3 and an FTDI-chipped USB serial adapter.. There's also a link there, to discussion about use of USB-to-TTL dongles or devices. If you assemble the CPU board only, you can wire it to a TTL to USB device and operate it under a ROM monitor in a similar way.

To support and upgrade earlier Membership Card versions, look for the list of previous versions on this Web page. Read those support Web pages, for notes and links to other Web documents. There's notes on changes, and on ways to add RAM and ROM, and to build serial and USB interfaces. These "old notes" are also informative about use of the current revision - that's the other reason we keep them around.

Parallel and binary interfaces: Beyond connecting to binary devices, another choice is to attach an external controller or microcomputer to the 30-pin signals of the 1802 Membership Card. (In previous versions, there was a IBM PC type parallel-port DB-25 connector). With an external controller, one can load software into and operate the Membership Card. Various M/S Card owners have attached PIC, 8051, Arduino controllers. See this Note about use of the parallel port by old PC's, with links to examples of use of microcontrollers. The hardware interface can also be driven by 1802 programs, like any other microcontroller. Here's a project to plug into the DB-25 with a ROM, counter and serial port.

ROM monitors: Lee Hart provides binaries on-site and seperate ROM kits. See his distribution and sales Web page. So you could buy a ROM with a monitor or BASIC; or burn one yourself into an EPROM; or ask someone to do that for you. On this Web site there are links-to or Web pages of, a number of ROM monitors, FORTH, BASICs, available in 1802 source and/or binary; and 1802 assemblers. Details of some software are on our Software Web page.

Audio cassettes for data: You could implement a simple audio cassette interface, to load and save data. In 2012 in the cosmacelf Yahoo (now groups.io) discussion group, about recovering data from audio cassettes used for data storage on VIP's and SuperELF's. Here's my gloss of VIP cassette data storage and here's my gloss on SuperELF and other cassette data storage There's links to work done in 2018 to recover RCA's COSMAC cassette tapes, including new software tools. I describe hardware too. So you could implement these on the Membership card! to see how cassettes were used on other vintage computers, check this Web page of mine. Lee Hart's 1802 single board BASYS also had a cassette interface.

More history of development and applications

Lee Hart has produced a graphic of how the "elves" run the 1802. Lee also constructed some Membership Card operating notes and an 1802 instruction set summary. These can be printed and stored in the Altoid case. Here's the operating guide PDF version.

Lots of 1802 hardware, from the original ELF to the Membership Card, are discussed or documented on the groups.io cosmacelf ELF 1802 discussion group Web site. The corresponding Web site is cosmacelf.com.

Software notes and links

"How do I load and run a program?"Here's a Web page on how to operate the Membership card. There's examples, too. I made a YouTube video to "toggle Q", shows how to enter, verify and run the program to flash the Q LED. The code is in the Web page linked in this paragraph. You can also see the code in the video with closed captioning.

Lee Hart provides a BASIC, a Tiny BASIC, a ROM monitor and other software. They are provided as binary images for ROMS or binary download into RAM; or in a ROM kit. See my links to Lee Hart's 1802 M/S card sales page and look for that software. Details and documents are on his site. Here's operation of the Rev J M/S card with a BASIC 3 ROM and an FTDI-chipped USB serial adapter.

This links to my Web page of the software I and others have available for the 1802 and the 1802 Membership Card. On this Web site, there's a Forth called 8th, a Tiny BASIC, a cross-assembler with C sourse, and PC parallel port software to drive the Card. On other Web sites, there are a C compiler, 1802 emulators for specific COSMAC computers, Membership Cards operated with Raspberry Pi or Arduino, and more. Some other 1802 related Web sites are listed elsewhere on this Web page.

"Here's a free-running, slow counter in 10 bytes: EF 80 BF AF 9E 5F 1E 64 30 01 . Can it be done in 9?" - Dave Ruske

Lots of 1802 software - assemblers, compilers, interpreters, monitors, 1802 assembly code - is discussed or distributed on the groups.io cosmacelf ELF 1802 discussion group Web site. The corresponding Web site is cosmacelf.com.

1802 news, history, events

Prices and ordering info for current 1802 Membership Card boards and kits are described at this link.

July 2022: jump on reset. The new Rev L CPU supports a jump-on-reset feature. Hold the IN button while toggling the RESET switch, and the 1802 will briefly execute code from the "HI" jumpered ROM (or RAM) instead of the "LO" jumpered ROM or RAM. Then high and low memory are restored. This supports low-RAM / high-ROM operations.

May 2022: front panel numeric display. The new Rev L front Panel supports two or six 7-segment LEDs, with a ROM to display hex or ASCII characters. See the recent Rev L front-panel products for details.

June 2021: Diskless Elf/OS ROM available Diskless Elf/OS ROM by Mike Riley gives you a taste of everything! It has Tiny BASIC, FORTH, Lisp, VTL2, a monitor, simulator, a mini-editor/assembler, and XMODEM upload/download. See links to the 1802 Membership Card sales page for the binary ROM image and details.

Nov 2019: a CPU-only kit of the 1802 Membership Card, with CPU ROM and RAM. See the 1802 Special Kit Web page for details and how to order. By 2022 this became a regular alternative kit.

Sept 2019: Lee Hart and others displayed the 1802 M/S card and other COSMACs, at the VCF-Midwest 14 near Chicago.

Dec 2018: An article on the 1802 MC was published on EEWeb, by Max Maxfield. Microcomputer Retro-Kits That Fit in Altoids Candy Cans covers the 1802 MC, and points to Lee Hart's other Altoids-class microcomputers.

Sept 2018: Lee Hart and others displayed the 1802 M/S card and other COSMACs, at the VCF-Midwest 13 near Chicago.

May 2018: Herb Johnson demoed and sold the 1802 M/S card, at the VCF-East 2018 event in Wall NJ. Look for "Vendors", "RetroTechnology.com" for references and photos; the Web page references all the vendors, exhibits, and talks. Here's a photo of the 1802 M/S Card in the wild, running BASIC3.

Sept 2017: Lee Hart and others displayed the 1802 M/S card and other COSMACs, at the VCF-Midwest 12 near Chicago. Look for "VCFMW/ECCC12 (2017)" on that Web page, for a list of Web pages of photos.

Apr 2017: HErb Johnson displayed and sold the 1802 Membership Card at VCF-East 2017 in Wall NJ. There were many vintage computing exhibits, and several vendors. Here's my table.

Sept 2016: The 1802 M/S Card was sold by Lee Hart at the VCF-Midwest Festival 2016, near Chicago. Lee and several M/S card owner-developers gathered to mark the 40th anniversary of the COSMAC ELF. They provided a hand-wired ELF kit as a prize; and an ELF design modified for modern parts. Photo from Dave Ruske used with permission. Read this report from Lee Hart about the event, describing the 1802 exhibits.

April 2016: The 1802 Membership Card was sold at Vintage Computer Festival - East XI in Wall, NJ.

Aug 2015: Lee Hart and the 1802 Membership Card appeared at Vintage Computer Festival - Midwest near Chicago. "A guy at the show was intrigued by the 1802, learned its instruction set from the little fold-out card, and wrote a little program to "krell" the Q LED. This means sending pulses of different widths to the LED, so it gradually gets brighter, then fades back out, and repeats. The name comes from the old "Forbidden Planet" movie, where all the lights on the control panels did this.

June 2015: A gallery of 1802 Membership Cards is shown on Dave Ruske's cosmacelf.com Web site. That's a premier Web site for ELF and 1802 information. Dave Ruske also moderates the groups.io cosmacelf discussion group.

[VCF-E 10]

April 2015: The 1802 Membership Card was sold at Vintage Computer Festival - East 10.0 in Wall, NJ. The image shows an old laptop as terminal, operating the M/S card IDIOT monitor via serial port. The "kit" Herb Johnson sold at VCF-E, with serial connector, IDIOT monitor ROM and RAM, is described on this linked Web page.

The March 2015 issue of IEEE Spectrum magazine, an academic-oriented publication for electrical engineers, is an article by Stephen Cass on the 1802 Membership Card. "...Here Comes the COSMAC Elf" features some mention of ELF history, features of the 1802 and the Membership Card, and links to this site, cosmacelf.com and Lee Hart's sales site. A good number of kits were sold following publication. In a follow-up blog entry Stephen describes how he used an Arduino Mega to "drive" the M/S card and load and run programs, and to drive a MAX6971 to operate a 2-hex-digit display.

Vintage Computer Festival Midwest in 2014 included Lee Hart at an exhibit of COSMAC technology Including the 1802 Membership Card. Chuck Yakym, Dave Ruske, Josh Bensadon exhibited as well.

Vintage Computer Festival East in 2014 included an exhibit by Herb Johnson of the Membership Card and other COSMAC technology with COSMAC items from Bill Degnan, the Sarnoff Collection, Kyle Owen and Flash Corliss.

During May 5-6 2012, a Membership Card semi-kit was shown at my S-100 computer exhibit at the Vintage Computer Festival - East 8.0. near Wall, NJ USA. I previously showed the Membership card on May 14-15 2011 at the Vintage Computer Festival - East 7.0 at the same location. The flyer is based on the product sheet Web page. A number of people knew about the Membership Card, or had owned various ELF kits over the decades.

Lee Hart explains why he designed the Membership Card in these notes to HackADay, a popular site for individual projects.

Archives of RCA documents and artifacts including 1802 COSMAC and CMOS development history, were moved from Sarnoff Labs to various institutions in 2009-10. A museum display of artifacts is at one venue. I've collected some stories about techs and engineers who used, or who now own, early COSMAC development products.Read the linked Web pages for details.

Current and out of production versions

Prices and ordering info for the current 1802 Membership Card boards and kits are via this link.

Rev L Front Panel with Rev L1 CPU, is in distribution since Mar 5 2024. The Rev L front panel continues in distribution. The Rev L1 CPU has minor fixes from Rev L to support different speeds of RAM and CD4013 flip-flops, details given on that L1 Web page.

Rev L Front Panel with Rev L CPU, is in distribution since July 2022 The Rev L front panel continues in distribution, offering a 2 or 6 digit display under program control. The Rev L CPU offers a jump-on-reset feature to address ROM at 8000H on reset. Fixes to the Rev L CPU to match Rev L1 are now described.

Rev L Front Panel with K4 CPU, was in distribution since May 2022 until July 2022. The Rev L front Panel is a major change from previous front panels with the addition of 7-segment LED's and the removal of the DB-25 I/O connector.

Rev K4 CPUis in distribution since June 2021. The Rev K front-panel continued in distribution. Some minor component and layout changes.

Rev K3 CPUwas in distribution Sept 2020 to June 2021. The Rev K front-panel was in distribution from Sept 2020 to April 2022. Some minor component and layout changes.

2020: ROM and RAM kit with BASIC and/or ROM monitor is now available, sold seperately from the kits and boards.

July 20 2019: Rev JK2 Rev K2 CPU is in distribution; Rev J front-panel is still in distribution. The K CPU's 74HC244 input buffer was replaced on the K2 with a 74HC541, to eliminate extra power consumption during the time between CLEAR and the first LOAD cycle. See the JK2 Web page for details.

Nov 2019: There's a "Special" one-card version of the 1802 Membership Card kit. It's just the CPU board, with 1802, ROM and RAM. See the 1802 Special Kit Web page for details and how to order. This offer ended in 2022.

"Rev J2" was in distribution as of Jan 20 2019. That's the Rev J2 CPU board with Rev J front panel is in current distribution. The CPU's 4093 is replaced with a 74HC132. See the Rev J2 Web page for details.

"Rev JK" was in distribution as of Aug 1 2018. That's the Rev K CPU board, and the Rev J front-panel. The Rev K CPU changed the operation of the CPU clock. Here's the Rev JK support Web page link.

"Rev J" CPU and Front-panel were in distribution as of July 1 2017. The front panel had some changes from Rev I. No change on the Rev J CPU board; its distribution ended Aug 1 2018. Here's the Rev J support Web page link. Rev J CPU was retired in Jan 2019.

"Rev I" was in distribution as of Feb 1 2017 as a front panel, and since April 2017 as a CPU board. Here's the Rev I support Web page.

"Rev H2" was in distribution as of June 4 2015 as a CPU board, with Rev H front panel, until Jan 31 2017. Here's the Rev H and H2 support Web page.

"Rev H" was in distribution as of Apr 21 2015, and as supplies lasted after Rev H2 which was a minor change. See the Rev H support Web page.

"Rev G" was announced in mid-Feb 2014 and is out of production as of mid-April 2015. Here's the Rev G support Web page. Some Rev H CPU boards were distributed with Rev G front-panel boards; that too is supported on the Rev G support page.

"Rev F" was announced in May 2013 and is out of production as of Feb 2014.Here's the Rev F support Web page.

"Rev E" was announced in Jan 2013 and is out of production as of May 2013. Minor changes in PC board layout. Here's the Rev D & E support Web page.

"Rev D" was announced in July 2012 and is out of production as of Fan 2013. Here's the Rev D & E support Web page. Changes from Rev C to D include customer options to change the I/O port address, to stack two CPU cards to double ROM/RAM and double I/O ports, and to provide 8 bits of output on the DB-25 connector.

A "Rev C" card set was announced in July 2010 and sold through June 2012. There's very minor changes from the Rev B, plus an additional PC board as a printed front panel cover. Here's the Rev C support Web page. with construction manual and schematic. Supporting information about the Rev B also applies to the Rev C.

A "Rev B" card set was announced in mid-August 2010, and sold through July 2011. Here's the Rev B support Web page.

Several "Rev A" prototypes were produced in late 2009 and assembled and tested in 2010. Rev A Web pages are still available and useful. Here's a photo of the assembled Rev A 1802 Membership Card. Later versions look and operate almost the same.

Here's a more detailed history of 1802 Membership Card production.

History of the COSMAC 1802, ELF, and the "Membership Card"

[1802 prototype] A breadboard of the Membership Card circuits. Ode to Eight Bits, by Lee Hart

RCA research (later called Sarnoff Labs) developed the CMOS product line in the early 1970's, including the COSMAC 1802 CMOS microprocessor and other support chips, including software and development hardware. I've collected some stories about techs and engineers who used, or who now own, those early products. Some of RCA's history including COSMAC development, has been preserved in various venues as "Sarnoff Collections". RCA's lead COSMAC design engineer Joseph Weisbecker, also developed the "ELF" ,and wrote a construction article for it in Popular Electronics published in August 1976. It's a very simple kit to hand-wire, and to program the 1802 with nothing more than toggle switches. Over the decades, variations of Elf-like 1802 products and kits were produced in an almost continuous run.

In 1978-9, 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.

Many ELF derivatives were produced in the decades since the 1975 ELF. ELF and and related 1802 products have been discussed for some time groups.io cosmacelf ELF 1802 discussion group Web site, the Cosmac Elf Web site by Dave Ruske, and other Web sites. A Web search will find them.

Lee Hart's Membership Card itself is a product of years of discussion among "cosmacelf" enthusiasts. What follows is a summary account of Lee Hart's 1802 work leading to the 1802 Membership Card.

In May 2008, I found out that Lee Hart wanted to resurrect his old 1802 FORTH; I and others helped to gather old code and documents to do that. That's when I found his earlier discussions in cosmacelf about his "membership card". By 2009, Lee was encouraged to pick it up again. He built a prototype and in October 2009 produced a few boards. I found a cross assembler in source form and made that available. I established these Web pages on my site to support the work, and to capture and make available his design discussions. See the Membership Card development page for years of discussion about the Membership Card design, and the philosophy behind it.

By February 2010, he produced several "Rev A" cards. After a chip change, in August 2010 he produced a "Rev B" production run, and kits continue to be produced and sold. Various versions have been sold continuously to this date, six years plus as of 2017. The most recent status of the project, and contact and price information, are given above. Here's a link to Current and previous version support pages.

other 1802 resources

The cosmacelf groups.io email discussion group and the Cosmac Elf Web site by Dave Ruske are notible resources for ELF, ELF derivatives and the 1802.

CHIP-8 was an 1802-based small interpreter of a 16-bit emulated processor with simple graphics. It was developed on the predecessors of the 1802, and forms of it ran on RCA COSMAC products including the VIP, Studio 2, and other machines. People in the era, and again in the 21st century, have migrated CHIP8 and varients to many vintage computers and to modern microcontrollers and computers. There's a bunch of CHIP-8 games that in principle can be migrated across many of these platforms. There's too many CHIP-8 resources to mention in the 2020's; a Web search will find all kinds of github sites, discussion groups, gaming Web sites, and so on. (Watch out for honeypot Web sites that try to prey on gamers and feed you malware!). But CHIP-8 programs for the 1802, can be found on the EMMA 02 Web site as part of their emulations for every 1802 computer ever made.

Documents and articles

Lee Hart suggests A Short Course In Programming by Tom Pittman, provided with permission.

Another classic 1802 guide is Tom Swan's programmers guide to the 1802 Swan authored this book in the era. He's providing this and other books he's written as PDF files. Details on his Web site.

Lee also says "The RCA Microtutor Manual is a good place to start. It was written by Joe Weisbecker himself (inventor of the 1802), and starts right at ground zero, for someone with zero prior microcomputer experience." This is not available online, apparently. Copies and originals are not uncommon.

He also suggests a look at the orignal ELF articles from Popular Electronics. are on Rich Cini's section of the classiccmp.org Web site. The Web page is an index of many documents, look for the Cosmac ELF PDF's. Other sites will likely have copies of these articles.

1802 history in space: See this Web page for details about the COSMAC in space. Please note: contrary to prior information on the Web and elsewhere, The 1802 was not used in the Voyager or Viking planetary spacecraft. It was used in Galileo, and in other craft prior and after. In fact, the COSMAC was likely the first microprocessor to operate an Earth-orbiting satellite. Read the linked document for details and primary references to confirm. Steve Gemeny, an active member of Yahoo's /groups.io cosmacelf group, contributed his first-hand information. He worked on a number of NASA spacecraft projects at the Johns Hopkins Applied Physics Laboratory (JHU/APL). - Herb Johnson

Web links to other ELF 1802 sites:

Many of these references were discussed in the cosmacelf group.
The EMMA 02 COSMAC Emulator emulates *many* 1802 boards and systems;
Mike Riley's Elf Web page with micro/Elf and pico/Elf designs and considerable software;
Elf 2000 from Spare Time Gizmos (not in production);
use of the ELF2K ROM on the 1802 M/S card;
the tinyELF emulator for Mac OSX (PowerPC or Intel versions);
an ELF simulator in javascript from Poland;

Matthew Mikolay, AKA mattmik has posted on his Web site the book Programs for the COSMAC ELF by Paul C. Moews; and issues of "VIPER" newsletter. VIPER was produced by Terry Laudereau and later Ray Sills. The "Programs" book is online with permission of the author.

Ted Rossin's RCA 1802 Web site. He has a C compiler, 1802 simulator, some PIC support from the 1802, lots of ELF work old and new.

The chip8 Web site is dedicated to current versions of the CHIP-8 game program language developed by COSMAC developer Joseph Weisbecker. Apparently CHIP-8 was reimplemented numerous times in the decades since the COSMAC ELF, for graphical calculators; then as a general emulator in the 1990's. It seems to be one of the subcultures within vintage videogaming culture.

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