Originally Posted by
kenpovey
:wee:
theory is it should be driven from a BBC printer port, this isn't a million mile different to a PC parallel print LPT1 port, so next job make a simple Parallel breakout board
Unfortunately the 1MHz bus is quite different
Then if all I have read is true I should be able to use almost any software ie. Coreldraw, Autocad, after all you are just sending HPGL code to a print port.
and if this doesn't work, I do already have Bobcad Ver20 which they asure me will work, but if it doesn't I may use the steppers on a small lathe 'cause a tail stock would be very desireable then use Hobby co stepper driver kit, infact I already down loaded freeware software for it.
The stepper drivers are easy to access, just need a step & direction signal.
Unfortunately the onboard Z80 has all the smart firmware for spindle motor speed & sync, as well as the stepper moves.
The BBC floppy is copy protected by swapping a couple of tracks and hiding critical boot data out of readable area. Anyway, getting old floppy drives is hard these days. I used to read/write double density floppies on a PC, and also run a BBC emulator on a PC for writing programs. It was nice to watch the tool path as you typed in a line.
However, the software is so bad & buggy, it is better to use 3rd party lathe drive software and connect up. Wire up the steppers & manual interface to the parralel port. Also DAC spindle control and hook up the spindle opto sensors for feedback and position sensing for threading.
I have even drilled the spindle sensor disc on a friend's lathe for quadrature encoding for better thread cutting tolerance.
Ken