[Coco] [coco] Coco CNC
gene.heskett at verizon.net
Wed Feb 13 21:17:41 EST 2008
On Wednesday 13 February 2008, George Ramsower wrote:
>From: "Gene Heskett"
>> Yeah, I've been meaning to ask how the coco is actually interfaced to the
>> motor drivers, can you clarify that George?
> Years ago, I built an interface board that connects to a Y cable. On that
>board is a 1 of 16 decoder addressed to the last bit.
> Also there are four 8 bit output latches and four input buffers. This uses
>a total of eight address spaces starting at FF60.
> FF60-FF63 are the output latches. FF64-FF67 are the inputs.
> Those are wired to DB-9 connectors. Those outputs are connected to an
>external box that has a 24V power supply and four ea. four darlington
>transistor arrays that step up the 5V signal from the coco and provides the
>current for the steppers.
No dmos h-bridges? They are the ideal motor driver. See the Alegro A3977 for
> In that outside box is also a provistion for one input array to one of the
>input buffers on the coco. Right now, I'm only using three bits for the
>three home switches on the XYZ axis'.
> It's really quite simple.
> FF60 is the X axis. It uses only four of the eight bits and so on..
> Originally I put two steppers on one latch, but the math slowed the poor
>coco down. Since I only need four axis, one per port made more sense and I
>switched to that ideal.
Sounds like the nearly ideal situation. I can visualize it nicely. Unforch for
EMC, the pc's existing parport was the chosen interface for EMC, and if it
weren't for some smart software, that port would be a bit crippled, but we
can run 4 motors and tally the home switches for a 4 axis machine plus a
surface probe, using just the parport. But I have another dual parport card
that will be installed when I switch the driver from a 3 axis board to a 4
axis board, and that will let me do a few more things, like run the lathe
too. But that is down the road, possibly to a bigger lathe before that gets
wired up as the carriage on this one would be hard pressed to support even a
262 oz motor. The bigger lathe means a bigger building, and that's self
feeding until the account is drained. Darnit.
> I built this coco for the purpose of home security and just playing with.
>But when I decided to make a CNC machine, it was already set up (hardware
>wise) to do this. I didn't have to modify the coco at all. Now, when I want
>my security thing, I just unplug the CNC machine and plug in the security
>stuff, pop in another 3.5" floppy, reboot and viola! A computer can be
>whatever we wish.
Limited only by our imagination. :)>
> What FUN!! I love my cocos!!
> This is almost as good as sex!!...... almost.
> Anyway, it's a danged site better than TV, now that the Writer's Guild is
>taking a vacation.
> Damned unions.
> Greed is why we are approaching a recession. I could go on and on, on that
>subject, but there's not enough room in my coco for all what I think on
And to expand on that, the large fraction of a terrabyte worth of disks in
this box still doesn't have room for my opinion on the subject of greed, and
it certainly isn't printable.
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
It's reassuring to know that if you behave strangely enough, society will
take full responsibility for you.
More information about the Coco