What I said to Russ was that he could easily use his programmable logic board about his use of which he wrote at some length in another thread, to create the logic to generate whatever cyclical but arbitrary waveform he wants. The PC is involved only to the extent that it is used to program the FPGA/CPLD on whatever board he is using. Since the software with which to do this Windows-based, it runs under Windows. Aside from that, no further PC involvement is needed.

However, I use PC's under DOS, via the parallel port quite often to stimulate or record systems under study. I can do this via BASIC, 'C', Pascal, Fortran, Prolog (which interfaces nicely with 'C', BTW), or whatever.

I have numerous PC's that I've had around for some time, and more of them are relegated to test and measurement all the time as I upgrade. I keep the ones that I can't give away to needy individuals, though I admit I've become accustomed to the quirks and foibles of some of the ones I've used a lot. I have so many of them that two are sitting in the back seat of my car right now because I don't want to bring them in the house. Old PC's are like puppies ... it's not easy to find them a "good home."

Old Windows-9x-equipped notebooks make very convenient platforms for testing and monitoring. You often see them for sale, fully functional, for less than US$50.

Under DOS, you have access to the timers, DMA, and the parallel port, as well as the serial port, if you can use it. The sound system is also marginally available, though, under DOS, it's a mite painful, and often requires an external amplifier to be of any real use.

The handshaking signals on the serial port provide a handy means for driving power FETs that require gate voltages beyond 5 volts. The MIDI/Joystick connector provides a useable source of 5 volt power to the outside world, too, if you need it. There are probably other uses, but I've not explored that.

I have many dozens of MCU's sitting on the shelf. Still, if I need a signal to go high for 100 ms, and then go low again for 2 seconds, a PC is an easy way to generate that. In the process it can even tell you what other signals are doing and echo that information to the CRT or a file.

RE