End of day notes...

So, got the stepper controller part of this whole deal put together and working on a prototype board this evening, spent the rest of the day tracking down a current vector graphics drawing program and using it to get started on a PCB layout. For all the more complex PCBs I've made in the past, I used an ancient copy of Corel Draw 4 to do the artwork, which is a little inconvenient since it requires hooking up the old computer we've got it installed on to do board layouts. Corel 4 wasn't the ideal program to work with from the beginning since it uses a proprietary file format that nothing else on the planet understands.

Ran across an open source vector graphics program, Inkscape, which I'm super impressed with so far. Very clean and effective UI, I haven't noticed any glaring deficiencies or broken features, and the windows port works great! Haven't had a chance to test the linux version yet, but from what I've read it should work just as well. Very nice example of quality GPL software! Inkscape uses the SVG (Scalable Vector Graphics,) which is nice since it's open source and pretty well supported (firefox, for instance, can view SVG files.)

With the USB controller that I'm working with (a Cypress unit preprogrammed by Delcom Engineering,) I've decided to build the step pulse clock with discrete parts rather than doing it in software to get more speed and smoother movement out of the motors, so will be putting that together as soon as some more parts come in the mail... Guess I'll order that stuff tomorrow. The idea is to build a little D->A resistor network hooked up to the USB controller and tie the output of that to a voltage->frequency circuit. To count out the pulses, I'll have a serial->parallel shift register hooked up to the USB controller and latch the output of that into a down counter (unless there's a serial down counter on the market...) The clock on the down counter will be connected to the V->F circuit so that the USB chip can set both the pulse speed and count, but the actual timing of the pulses will be controlled in hardware. Should be able to impliment fairly smooth ramping using that method as well, looking forward to getting it all put together and playing with different options...

But, my eyes have been burning for a while, so off to bed for now!