"Richard Erlacher" <edick(a)idcomm.com> wrote: Hi Dick I use a PC to develop on. I don't have enough ROM space on the 4004 system to do very much. The developement system is currently running the code that came with it. It was intended to program 1702A's. It does this well. I am writing code to make a 4 function calculator that runs through the serial line used for the programmer. I've desided to use BCD math since it has instructions built in that deal with doing BCD corrections. The RAM orginization is well suited for 16 digits of BCD for each data value. To get copies of my tool set, down load: ftp://ftp.hal.com/pub/elvey/I4004.ZIP You'll also need a Forth interpreter because everything is in source and not precompiled. I used the Freeware Forth called FPC. You can download a copy from the site: http://www.forth.org/compilers.html I also included tools to convert Intel hex to binary and back for those that need this format for their particular programmer. There are some assembly example files called *.AS4 that will get you started. Let me know if you have any questions. You don't need to know Forth to use the tools but you can do more advanced things if you do. For the most part, the READ.ME file should be enough to get you started. What is your interest in working with the 4004? Dwight