Re: 5-axis machine controller

[Brian Pitt <bfp-at-earthlink.net>]

> That is sure what I get from reading it as well.
> It is a driver for specific hardware.
> BUT, something I never did see mentioned is if I'm reading it correctly you
> should be able to simply stick a pair of 74139 TTL Dual 2-to-4 Decoder
> Chips on the outputs and off you go. The 2 bits select ONE of 4 outputs
> wired to each of 4 phase driving transistors and you are done.
>
> You can't drive more than one phase at a time and so won't be able to 1/2
> step but this is almost as simple as directly driving the 4 phases from 4
> bits. It would allow twice as many motors to be driven from a regular
> parallel port.

yep that would work for wave steping
or
for a four-phase stepper  two-windings-on step sequence
rename phase-A & B to coil-A & B
and add an inverter (2ea 7414 for all 6 motors) so that
coil-A
	wire-1= true 
	wire-2=!true

coil-B
	wire-3= true 
	wire-4=!true

gives 
(more of the TABs here)
  dir   p13  p19	   coil-A	   coil-B
			wire-1	wire-2	wire-3	wire-4
  |  ^   0    0	=	 0	 1	 0	 1
  |  |   1    0	=	 1 	 0	 0	 1
  +  -   1    1	=	 1	 0	 1	 0
  |  |   0    1	=	 0	 1	 1	 0
  v  |   0    0	=	 0	 1	 0	 1

still cant half step but gives a bit more torque
basicly replaces the standard step/direction translation circuit
for a simple unipolar setup

Brian