Builds of the 1802 Membership Card

Last updated Apr 26 2018. Edited by Herb Johnson, (c) Herb Johnson, with content written by others.

Builds and microcontrollers and the 1802 Membership Card

[Rev I] [unassembled kit]

Lee Hart's 1802 Membership Card kit, is a modern "build" of the ELF COSMAC computers of the 1970's. It is built around the RCA COSMAC 1802 microprocessor, with RAM and toggle-switches and LED's - almost nothing else! But it's simple to build yourself, and you can toggle-in or load and run microprocessor programs to control inputs and outputs. See my home-page about the 1802 M/S card and kit for details. From that Web page, there's links to hardware, software, past versions, and how-to-use.

The 1802 Membership Card will be EIGHT years old in 2018; many people have bought and built it. Here's some noteworthy "builds" of the Card, and how some have operated it with modern "micros" or with modern software. - Herb

Builds of the 1802 M/S Card

The "hardware" Web page has links to how-to-build or modify the 1802 M/S Card, mods for past versions, issues of interfaces and connections, low-power or high-speed operation. This portsion of this Web page describes how owners have built their kits.

[Altair case] [Altair case]

Sage Hansen in 2018, sent photos of his 1802 M/S card build, with these notes. "I really like the 1802 Membership Card! It is so rewarding to toggle in programs and see it run. Thank you for making this. I wanted to make a case to hold the computer, batteries, and note cards. I thought it would be fun to make the case look interesting. So I made it look like an Altair 8800 computer! I know that that computer didn't have a 1802 microprocessor, but still it is of that era and represents those early toggle switch computers." Sage Hansen has a YouTube channel "3DSage" of his 3D prints and experiments in PC boards and computer logic.

[Altair case] Lee Hart built a solar-powered 1802 M/S card, in late 2017.

Lee Hart in 2016, put an 1802 M/S card in a model of the Galileo spacecraft that went to Jupiter (the NASA craft, not the model!). The Galileo spacecraft had several COSMAC 1802's to operate the various experiements. It was chosen because of its low power and radiation resistance of its CMOS architecture. The Web page has more notes and links about COSMACS used in spacecraft.

David Kriest in June 2014, assembled a Rev G CPU card as a stop-motion video. See the video on Youtube as "MC Revg" by "Corecoder" for June 13 2014.

P. Todd Decker completed and debugged the rev A kit in May 2010, and provided Lee Hart and myself with discussion about some design issues, resolved in the Rev B version. hear's Todd's assembly and debugging of a Rev A kit, including notes for a "single-step" device. Todd produced a demonstration video on YouTube in July 2010, titled "COSMAC 1802 Membership Card Checkout" by ptdecker. Photos appear on FLickr titled "1802 Membership Card" by ptdecker. Todd has a Facebook page as ptdecker.

Chuck Bigham completed a Rev B kit in Jan 2011. Chuck has connected his Membership Card to a Windows PC via a Pixaxe conroller. Check the software Web page for details and links.

Chuck Yakym built a Rev B kit in early 2011, and created a Windows 32-bit program (Win XP, 7) to access and program the Membership card through the PC parallel port. Check the software Web page for details and links. Also check the cosmacelf Yahoo site for other 1802 programs by Chuck.

Mark Moulding AKA "urrossum" built a serial loader for the M/S card in March 2012. It uses a ATMEL AT89C2051 as a serial to parallel converter. Here's a tech note about his work.

Mark Thomas has done considerable work on ROM and serial upgrades to the Membership Card. Here's a Web page about some of his ROM and serial work on Rev E and F versions which did not support those features.

The Rev A prototypes were constructed by a few people: here's my [Herb Johnson] build from Aug 2010.

1802 and modern microcontrollers, computers

The 1802 M/S card can be operated without any other computer, no programs - you can toggle programs in yourself, write them by hand in binary! But many people add a ROM and run software like BASIC, FORTH or assembly. The software Web page describes some of those programs. And some 1802 M/S Card owners run their cards with other microcontrollers, as described here.

Raspberry Pi interfaces for the 1802 M/S Card, were discussed on the "cosmacelf" Yahoo discussion group in 2017. One RaspPi interface is called "RaspiElf Tools" by Peter Schmid posting as spyrpsi. A RaspPi is wired directly to the 1802 M/S DB-25 connector, and a C program for the Pi to run the card. He has a version of the A18 cross assembler with Linux. No electronics or PC boards, just wires.

Another RaspPi interface is "ElfPi" by Len Bayles posting as ka7ftp. He designed an interface card for the RaspPi, to bring out two SPI-based MCP23S17's, to the DB-25 of the M/S card. Software on the Pi runs the M/S card at the toggle level to DMA in and out; I don't know if the 1802 can "talk back" to the RaspPi. A card vendor link, software, and Gerbers are on his site.

Bill Rowe's "olduino" is an aggressive M/S Card interface to an Arduino, plus a C compiler for the 1802, to support some Arduino applications run by 1802 programs. It's a very impressive set of work by Bill, over many years.

Chuck Yakym in early 2011, built a Rev B M/S Card kit, and created a Windows 32-bit program (XP, 7) to access and program the Membership card through the PC parallel port. His program and many others for the 1802 M/S card, are available from the Yahoo cosmacelf discussion group file archive. his control program is also available from me by permission. It's written in Visual Basic 5.0 and uses inpout32.dll. He provides switch-setting instructions for using the Membership Card with the parallel port.

In April 2015, Stephen Cass in an IEEE blog describes how he used an Arduino Mega to "drive" the Membership card to load and run programs, and to drive a MAX6971 to operate a 2-hex-digit display. He previously wrote an article in the IEEE Spectrum about the Membership Card kit he built.

Contact information for Herb Johnson:
Herb Johnson
New Jersey, USA
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