Welcome to my website!

Using an Arduino as an ACIA with the CDP1802
"Click here to go check it out."

Add a simple Input/Output interface to any microprocessor system
"Click here to go check it out."

Build a simple 8 Channel Analog-to-Digital Converter using a Microchip PIC
"Click here to go check it out."

In 2014, I was looking for a digital logic simulator to recreate a functional 1802 CPU using logic gates.
My Google search brought me to what I think is the BEST FREE logic simulator available. It's called Logisim and it was done by Carl Burch.
(If someone found another one that surpasses Logisim, please let me know so I may go check it out. For now, Logisim remains the defacto for me.)
"Click here to go simulate the 1802 CPU with Logisim"

After I did all the logic in Logisim, I decided to create all the schematics in the Altera IDE and using the DE0 FPGA development board from Terasic, I removed the CDP1802 chip from my ELF II, plugged and ran the DE0 in its place.
You may download the Altera DE0_1802CPU ZIP file here

For those familiar with CHIP-8 or are interested in learning other programming languages, please
"Click here to go check the CHIP-12 and CHIP-12 BASIC Compiler Page"

 Please note: This web site is a work in progress. I plan to add once in a while some electronic projects and software programs I did.

The following project is based on the RCA CDP1802 COSMAC Microprocessor.
Even if this microprocessor was introduced in early 1976, it is still one of my fondness microprocessors because, in 1979, one of my older brothers introduced me to the world of microcomputers and electronics..
He had purchased the Netronics ELFII kit and Giant Board.
So I saved up and bought the same kit also. Unfortunately, many years ago while cleaning out our basement, I decided to part with the kit, but I kept all chips.
In April 2011, based on my brother's Dec 1989 design, I decided to design and build a new ELF II.

NewELFII_01 (236K)

 NewELFII_02 (191K)
You may see the schematics here or you may download the PDFs down below. Please see NOTE and Errata also.

Addendum Jan 2018:

Since new laptops no longer have serial COM ports, I modified my design "using an Arduino as Serial ACIA"
Eventually, I will have a PCB fabricated once I'm done experimenting and satisfied with the new design.
Click here for NewELFII Version 3 schematics.
Click here for NewELFII V3 Altera schematics.
Click here for NewELFII V3 Arduino Nano/UNO source code.
In the early 1990's, I wrote a DOS based special 1802 Assembler.
In Nov 2011, I wrote a new and improved version in VB.NET.
You are welcome to try it out and let me know what you think of it.

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New 'ClickOnce' installation. Current version is 16 March 2013.
Help file will be installed also.

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This is the schematic of the New ELF II mainboard.
NOTE: The RS232 DB9 connector on Page 3 is configured as a DCE (Data Communication Equipment) device.
Therefore a straight cable is required.
Errata - on page 4, the Memory Address Decode should be as follows:
0000-7FFF = 62256 SRAM
9000-FFFF = 27256 EPROM or 2864 EEPROM
8000-87FF = 6551 ACIA
8800-8FFF = 2816 EEPROM

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These are the ALTERA files used to program the ALTERA chip.

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This is the ALTERA PLD schematic of the New ELF II.
1802ELFSim Web Page Link.
Please check out my 1802 simulator program called 1802ELFSim.
Please check out some of my other projects on how to:
"Build A Simple USB Digital Logic Analyzer"
Project date - 2 February 2016.

"Build A Simple Serial Interface Using VB6"
Project date - 7 February 2016.

"Connecting a 3.2in Display to the RCA CDP1802 CMOS 8-bit CPU"
Project date - 10 November 2017.

Contact Info: marcpic13@yahoo.com

Access to this page since 2 Dec 2011: 0000722Ch