Re: [CAD_CAM_EDM_DRO] Re: 4th Axis Concept (long)

Hi Tony,

Thanks for the reply! And the compiler URL. I'm using CCS

http://ccsinfo.com/

They're ALWAYS charging for updates, mine's not up to 877's, but we were
able to program them! My son used one in his NATCAR, a line-following
car for UC Davis class/competition. The 877's a nice chip. We have
interfaced LCD's already.

Let me know when you have a board ready, I'd be interested it playing
with it. And I'd like to see how you did the code too!

Alan KM6VV


tony@... wrote:

>
> Hi Alan -
>
> Its a 16F877, clocked at 20 MHz, programmed almost entirely in "C".
> Been there, done that with assembler in past lives - didn't fancy
> learning yet another way of programming on my hands and knees!
>
> The "C" compiler is a bit memory hungry, but very quick to develop
> stuff - the dev system runs under Windoze & includes a (software)
> simulation environment that can also emulate the common PIC
> peripherals - LCDs, keypads, digital I/O,...great stuff. You can do
> much of the testing without going near a PIC chip. The compiler is
> marketed by FED:
>
> http://www.fored.co.uk/
>
> The early versions were a bit buggy - they hadn't quite sussed the
> memory paging on the 16F877 & I found some of the bugs for them - but
> the current version (V7.0 or thereabouts) seems pretty solid.
> Handles code generation for a wide range of PIC devices. They do a
> good programmer & dev board too.
>
> My controller does a simple (linear) accel/decel on all moves - one
> start/max speed for jog & another start/max speed for the other 2
> modes. With a step/direction chip like the L297, the stepper drive
> code is pretty trivial. The hard bit (as with most computer-based
> projects) is getting a sensible user interface sorted out; also doing
> the math to translate angular positions to/from motor steps is a
> pain. Most of that is done fixed point in 32-bit variables - a
> nightmare constructing the expressions to guarantee that you don't
> get overflow/underflow.
>
> Thanks for the beta offer - will bear it in mind. First problem is
> to get some proper hardware together - the prototype is a breadboard
> job at the moment. There's a bit of work to do to get it into a
> sensible & buildable form.
>
> Regards,
> Tony
>
> --- In CAD_CAM_EDM_DRO@y..., Alan Marconett KM6VV <KM6VV@a...> wrote:
> > Hi Tony,
> >
> > Sounds great! Which PIC are you using? All .ASM, or some 'C'? Do
> you
> > do accel/decel? I've been wanting to get stepper code into a PIC!
> >
> > Alan KM6VV
> > P.S. I've got a CNC rotary table, PIC's, etc. if you want someone
> to
> > Beta.
> >
> > tony@j... wrote:
> > >
> > > --- In CAD_CAM_EDM_DRO@y..., Chris L <datac@l...> wrote:
> > > > Sheez, if this is this basic why is no one marketing such a
> little
> > > beast? You know
> > > > what they get for a small powered Indexer.......
> > >
> > > Talking of small powered indexers, I have a working prototype of a
> > > small powered indexer, based on a PIC microcontroller and a
> bipolar
> > > drive (L297/298), intended to drive a rotary table or dividing
> head
> > > fitted with a 400 half-steps per rev stepper motor. Brief features
> > > list (at present):
> > >
> > > - 2-line by 16-character LCD display and 16-key membrane keypad;
> > > - Setup parameters stored in Non Volatile RAM - remembers the
> > > settings from last time it was powered on;
> > > - Will cater for any worm/drive ratio between 1:1 and 99:1;
> > > - Adjustable initial/max feedrates and jog rates, from dead slow
> to
> > > around 60 degrees/s with a 72:1 worm drive (e.g., the Sherline
> rotary
> > > table);
> > > - Adjustable ramp rate;
> > > - Software-based backlash compensation;
> > > - Bipolar chopper drive - usual L298 spec (2 amps/phase), with
> > > chopping current settable via software;
> > > - "Jog Mode" gives CW/CCW jog in increments of 1/100th, 1/10th, 1
> and
> > > 10 degrees, with display of desired and actual angular position
> to 3
> > > decimal places (where the desired position cannot be achieved,
> actual
> > > position is within 1/2 step of the desired position);
> > > - "Division Mode" allows operator to set the number of divisions
> > > between 1 and 999. Table can be driven CW and CCW one division at
> a
> > > time - display shows current division number, plus actual angular
> > > position in range 0 - 359.999 degrees;
> > > - "E-Stop" key halts any move immediately, but the current/desired
> > > angular position is remembered - hence, position is not lost on E
> > > Stop.
> > > - "Degrees Mode" - similar to Division Mode, but the move is
> > > specified in degrees to 3 DP;
> > > - Motor connector is plug-compatible with Taig's CNC equipment (6-
> pin
> > > DIN plug);
> > > - Breakout connector provides for external control of CW/CCW moves
> > > and E-Stop, and also provides step/direction outputs if needed to
> > > control a higher power driver stage.
> > >
> > > I'm currently working on getting the board into production - watch
> > > this space.
> > >
> > > Regards,
> > > Tony
>
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