PicNPro from the web site below has all schematics PCB designs etc, as well as the programmer source code used in the project. With this information, you can write your own interface if you like, ie DOS, MAC, UNIX etc. It also has a real world port interface for both simulators and expansion pins to allow programming of 'other' types of chips. I'm just putting the finishing touches on an In Circuit Programmer mini board that will allow direct connection to the programmer to 'burn and run' 16F84s on the fly for further experimentation. It will plug into any solderless bread board and should only cost a few dollars to get going. This also takes advantage of one of the 16C74's A2D inputs to allow you to play around with a POT and read it's position into the simulator. This daughter board also includes space for 16C5X programming sockets and a section to connect the real world interface to a solderless breadboard. The board can be cut into four sections to take advantage of these features. I am using standard 40 pin sockets on all boards so that a single 40 pin ZIF socket can be plugged into them to program all the chips that the programmer can handle. I am hoping, for a limited time, to offer these experimenters boards free to new buyers of PicNPoke, although the designs will be presented as part of the software for those that want to roll thier own. By the way, the simulator now has interactive single instruction tutorials that are linked to the 'Binary Classroom' so you only need to click on a button to watch an instruction of your choice execute. -- Best regards Tony PicNPoke - Multimedia 16F84 Beginners PIC Tools. http://www.picnpoke.com Email picnpoke@cdi.com.au