Well, with no eprom programmer, I'd say that might be a good place to start. If you get a set of programming spec's for the EPROMs, EPROM-based MPU's, and EEPROMs, not to mention FLASH memory devices, that interest you, perhaps the thing to do would be to build a programmer using a PIC, SCENIX SX, or whatever you choose. The easy way to interface such a device is thorugh the parallel port, which has several operating modes, of which I like the EPP the best, but you can make up your own mind. Keep in mind, that you're building a tool that you're going to use again and again. Keeping it flexible might be a real priority. Most programmable parts are VERY easy to program by comparison with parts dating back to the '80's, and the 2716, in my opinion, was of all of them the easiest. There are few MCU's easier to program than the 8748, though you'll have a tough time finding them outside a scrapyard. Frankly, once you get past the notion of fiddling with voltages high enough to damage some of your circuitry if it gets where it's not wanted, you'll find this sort of thing quite straightforward and even fun. One advantage to using an SX, is that it's so fast you can use it to perform pretty accurate timing of the controls on a field programmable part. Whats more, if the code burden to waste time or synchronize with an external event is awkward, you can switch the clock speed with a programmable timer, though you need to take into consideration what that does to the internals, e.g. timer/watchdog, etc. Let me know what schematic format(s) you can read and I'll see if I can generate one of more of them. Dick ----- Original Message ----- From: Kevin Stewart <stewart_kevin(a)hotmail.com> To: <classiccmp(a)classiccmp.org> Sent: Monday, September 18, 2000 5:19 PM Subject: Re: Computer Kit / Plans like