Homebrew PCBs

Using a microcontroller to replace several discrete hardware 
components is where it's at but unfortunately that doesn't seem to be 
the case here. The Allegro UCN5804 and several other single chip 
unipolar drivers from the mid nineties (now obsolete) not only did 
that but also had built in high current drivers. Furthermore, IIRC, 
you cannot get any reasonable torque from this approach unless a 
voltage at least 5 times the rated voltage of the stepper is used in 
conjunction with current limiting ballast resistors. These resistors 
get very hot and have to be heat sinked. This is outdated technology 
and to mimic it using a microcontroller seems nothing more than an 
academic exercise in programming.


--- In Homebrew_PCBs@yahoogroups.com, Robert Hedan 
<robert.hedan@v...> wrote:
> Has this been brought to the attention of the group yet?
> http://www.dakeng.com/u2.html
> 
> It's a PIC 16F84 along with the Assembler code to convert standard 
TTL step
> and direction signals to the phase signals used by a unipolar 
stepper motor
> for two axes.
> 
> Robert
> :)
> 
> 
> 
> 
> 
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