Here's a schematic (PDF) for the simple circuit in the picture at the top of the page. It allows you to see the 1802 run through its address space, as every instruction decodes to a "NOP" (no operation). It's also a decent starting point for a more complex circuit that …

The Cosmac Elf is based on the RCA 1802 microprocessor, which was a relatively low-cost and low-power chip at the time. The 1802 was known for its simplicity and versatility, making it an ideal choice for the Cosmac Elf project.

The RCA 1802 has a static core CMOS design with no minimum clock frequency, so that it can be run at very low speeds and low power, including a clock frequency of zero to suspend the microprocessor without affecting its operation.

The RCA 1802 was a pioneering CMOS microprocessor. See our main site for some more information and images. Not only was the C2L CMOS process simpler, denser and faster than previous ones, it lends itself to radiation-hard chips, which led to …

In this, there was considerable effort made to assure an accurate, reliable and complete schematic diagram, dimension drawing, parts layout drawing, parts list and supplier list, along with this User’s Manual. The “1802 microprocessor” was originally known as the RCA CDP1802.

Jul 23, 2022 · User Manual for the CDP1802 COSMAC Microprocessor. Includes programming information and interfacing information. Reviews cannot be added to this item.

May 29, 2020 · RCA's 1802 8-bit CMOS microprocessor is to be supported by the Tektronix 8001/8002A microprocessor development lab. Because of its CMOS characteristics, the 1802 is widely used in severe environments and/or portable applications.

Nov 25, 2019 · The next step in my homebrew computer adventures is the Cosmac Elf. The Cosmac Elf was a DIY computer that appeared in Popular Electronics in 1976 and 1977 using the RCA 1802 microprocessor. The schematics that I used are here: ELF Schematic 1. ELF Schematic 2. Other good resources can be found here: http://www.sunrise-ev.com/vcf-elf.htm.

Program listings, logic and wiring diagrams, manuals, and other documentation for the Elf II microcomputer.

Oct 10, 2018 · The RCA 1802 was an early CPU, and a very early CMOS CPU, used for example in the COSMAC ELF evaluation board/kit computer. A chip was imaged in 2011 at high resolution by Greg of the Visual6502 team, with images here and some supporting analysis here.