Arduino Motor Shield for CNC machine

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Arduino Motor Shield for CNC machine

Postby teslas_moustache » January 20th, 2013, 2:31 pm

I got one of [these guys](http://ladyada.net/make/mshield/index.html) in the mail a while back. I'm building a small 2-axis CNC machine and one of my old stepper drivers just burned out (I think). So I thought this thing would be usefull since the ICs are in DIP.

The thing is I need to figure out which pins are the Step and Direction pins. The Arduino and Reprap IRC channels don't seem to have any answers. All information available seems to be about using the Arduino environment and whatnot. I'm not doing that. I flashed the Arduino with the Teacup Reprap firmware to interpret the G code and send it to the microcontroller. It looks like Adafruit didn't exactly intend for people to do this. They just have this library to be used with the Arduino environment. That looks like it's useful for pretty much everything BUT a CNC machine. All I need to know is which pins are being used for Step and Direction.

With the Easy Drivers, I could set that myself in Teacup's config.h file. But since this shield is fixed to use certain pins, I can't do that.

The first thing that comes to mind is trying every combination of pins for Step and Direction for the X and Y axes, but that requires editing the config file, re-flashing the Arduino, and then running some code in Pronterface to see if the motors move. Seems kind of tedious.

It would be awesome if someone out there knew how to figure this out.
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Re: Arduino Motor Shield for CNC machine

Postby semicolo » January 20th, 2013, 7:56 pm

Just download the arduino library and look in the source code, if you're lucky there are comments about the pinouts.
Maybe it's not dir and step but phase 1/phase 2. Anyway with the arduino library you should be able to figure it out
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Re: Arduino Motor Shield for CNC machine

Postby semicolo » January 21st, 2013, 12:44 pm

From the schematic it looks like there's a 74HCT595 driving the L293Ds Mxx inputs, so you have to send the data serially to the 74HCT595T and you can use the EN inputs to do microsteppings. I wonder if this way of driving ENs without feedback gives good results...
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