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Sammy1Am / Moppy2

The evolution of the Musical flOPPY controller
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Apple Floppies #13

Closed DJthefirst closed 5 years ago

DJthefirst commented 6 years ago

I’ve found some old apple floppies and they look like they have serial wires and pinnouts. I found some diagrams showing their is a pwm pin but no direction pin. is their a way anyone else knows how to drive them with moppy. (I’d rater not just drive the pwm signal to the motor as that just plays like as a speaker )

Lothean commented 6 years ago

Hello As far as I know, Apple drives are not compatible with Moppy, sorry You could still try to do some reverse engineering and create a Moppy instrument for them

Sammy1Am commented 6 years ago

Any chance you could share the pinouts/diagrams here? From my little research it seems like they definitely don't have the same super-convenient step/direction pins that the rest of floppies have, but it doesn't mean there's not some way around it.

(But out of the box, @Lothean 's right, probably not going to work)

DJthefirst commented 6 years ago

http://old.pinouts.ru/HD/MacExtDrive_pinout.shtml Here is the link for the page I found it on

DJthefirst commented 6 years ago

If you want me to modify the drive inside I can I have a 5” a 3.5” and another 5” mit drive but that has normal pin outs I’d send pics but I don’t think I can from my phone.

Sammy1Am commented 6 years ago

That's a better pinout than I'd found, but confirms my suspicions: rather than controlling the steps and direction with pins, the control line(s) are used to send commands and the drive handles the steps and direction on its own. I suspect the PWM to regulate speed might be more about regulating the speed the drive reads and writes bits to send over the data lines than the physical speed of any motors.

Because you can't use the pins on the drive interface, your next best option will be to drive the stepper motor directly with a stepper motor controller. You'll need to do some (de)wiring in the drive, but stepper motor controllers should be reasonably compatible with Moppy.

DJthefirst commented 6 years ago

It is a 6 pin stepper motor I’ll see if I can trace back the traces to the chip and if it has a pwm and step pin

Lothean commented 6 years ago

If it's a 6 pin stepper motor, it should be compatible with the DRV8825 or the A4988. The input voltage of these does not affect the motor (it needs to be atleast 8.5V), just set the current very low to start and see if the motor gets too hot. These previsously mentionned board are cheap, not hard to use for beginners like me and have the convenient STEP/DIR interface. As said on the Pololu website (they sell DRV8825) : "Some unipolar stepper motors (e.g. those with six or eight leads) can be controlled by this driver as bipolar stepper motors. [...] Unipolar motors with five leads cannot be used with this driver." https://www.pololu.com/product/2132

DJthefirst commented 6 years ago

The part I find weird is if I trace it back it goes to an ba12003 buffer and then out to the input. So it means it the stepper was driven by the computer?

Sammy1Am commented 6 years ago

Hmm, that does seem weird. On the one hand, "normal" floppies have their stepper motors sort of driven by the computer in that it says when to step (so it's not too far off from that), but on the other it seems weird that the computer would also need to track the current state of the motor (that seems more like an IC thing).

Lothean commented 6 years ago

http://www.datasheetlib.com/datasheet/733481/ba12003_rohm.html If it's the chip in question, it's a transistor array You need to go further in the research, give us details about where everything is connected ?