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EasyDriver Stepper Motor Driver
Replacement:ROB-10267. The new version fixes the silkscreen error. This page is for reference only.
The EasyDriver is a simple to use stepper motor driver, compatible with anything that can output a digital 0 to 5V pulse. EasyDriver requires a 7V to 30V supply to power the motor, and has an on board voltage regulator for the digital interface. Connect a 4-wire stepper motor and a microcontroller and you've got precision motor control! EasyDriver drives bi-polar motors, and motors wired as bi-polar. I.e. 4,6, or 8 wire stepper motors.
This is the newest version of EasyDriver V4 co-designed with Brian Schmalz. It provides much more flexibility and control over your stepper motor, when compared to older versions. The microstep select (MS1 and MS2) pins of the A3967 are broken out allowing adjustments to the microstepping resolution. The sleep and enable pins are also broken out for further control.
Caution: Do not connect or disconnect a motor while the driver is energized. This will cause permanent damage to the A3967 IC.
Note: Version 4.3 of the PCB has an error on the Current Adjustment silkscreen. The Min/Max labels are reversed. The correct direction for maximum current is counter-clockwise.
**Note: **This product is a collaboration with Brian Schmalz. A portion of each sales goes back to them for product support and continued development.
- A3967 microstepping driver
- MS1 and MS2 pins broken out to change microstepping resolution to full, half, quarter and eigth steps
- Compatible with 4, 6, and 8 wire stepper motors
- Adjustable current control from 150mA/phase to 750mA/phase
- Power supply range from 7V to 30V. The higher the voltage, the higher the torque.
- Schematic
- A3967 Datasheet
- EasyDriver Website
- Example Stepper Motor Control
- Example Arduino Tutorial in Portuguese
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I ordered a few boards. But with testing them i noticed soemthing wrong. On the pcb the adj MAX gives a Vref of 1.5 V and the adj MIN gives a Vref of 5V. 1 of the 2 is lying, don't know which one.
Also you suggested to lower the Rsense for lower amp range. This is wrong. The values should be increased to get lower max output amps.
Yup, the silk screen is backwards on the current version. Min and Max are reversed.
Also, I believe you are correct - you need to go up Rs value to get lower overall currents. Sorry about that.
That makes sense why my stepper motor got hot enough to burn my fingers and melt plastic. I'm surprised the motor still works. I now set it to "max" and after 2 hours its only warm with no heatsinking. I bought heatsinks+fans for my motors before I found out about this, oh well, I will have them for another project. Thats why comments are great; although I think important information like this should be placed in the description.
I would be very surprised if the EasyDriver was able to heat up your motor so hot that the motor got destroyed. In many industrial applications, stepper motors normally operate at temperatures that will burn fingers. They're designed to take a lot of heat.
Only the very, very smallest of steppers would be able to be harmed by the EasyDriver. It can only drive 650mA or so.
So elevated temperatures (on both the motor and the driver) are expected. That said, in many personal applications, full current is not necessary through the motor, and the current adjustment pot needs to be dialed back in order to get microstepping to work properly anyway. So running them cooler is not a bad thing if it gets you the speed you need.
So this driver can only support a power supply that is up to 750ma? It is kind of hard to find one that is near 30v under 750ma.
The closest i have is a 24v at 1000ma but that will fry the board right?
As long as you don't draw over 750mA, you'll be fine.
Anyone else had a problem with these failing?
I have bought 5 of them and am down to one board. Running the same motors with the same code. They work for a few times and then bleh.
Question: Why will disconnecting the motor when energized damage the driver IC? I get the bit about inducted voltage needing somewhere to go, but the vast majority of the inductance would be in the motor windings, no? So if they're disconnected, the motor, not the IC, suffers the voltage spike, right?
The description reads "EasyDriver requires a 7V to 30V supply to power the motor, and has an on board voltage regulator for the digital interface." Is there any reason I couldn't power this board with a 12V Auto battery? I'm a little concerned about the Amperage available through this power source.
Car batteries are 12v @ 20Amps~40Amps.
I don't know why but my stepper (stepper from Sparkfun) is not moving when powered. Without power (12V) the motor is working with the Easydriver (although not very accurate even with high delays). But with 12V the motor just locks (nice torque!). Could this have to do with the wiring of the motor?
I'm using red, green (A), yellow, blue (B). Seems to me those are the motor specs of the coils.
I'm only using step and dir (Easydriver 4.3).
Does anyone have an Eagle component layout for the EasyDriver. I want to mount it into a parent board.
Thanks
Member183228:
Try this.
1) Left to right, plug your motor wires like this - G-R-Y-B. Help?
2) You could have a bad motor. Does it turn by hand easy when turned off? I saw some stock was bad here.
3) Check your ohms at board between green-red and yellow-blue. At 200ohm setting, you should around 36-40ohms. If zero, redo your wire harness.
4) BTW. What header blocks did you use? Mine don't fit or stay in the board. Pop back out.
it was actually hard for me to get those readings. First i was doing it with the power on, which i found out i shouldn't. but odd thing was when the power was on, i was taking the reading and the motor started to move. whats that mean? However, the subsequent readings i got before and after the power was off were between 30-40 ohms. Those Terminals im using are from radioshack http://www.radioshack.com/product/index.jsp?productId=2102861# The spacing is .19 so i just bent it .01. I did that to test to see if the problem was with the Spring Sparkfun terminals i bought.
Is your BB rail a split rail? I can't tell, but try this for kicks.
1) Plug source +/- into left/bottom rails.
2) power jump both devices from the left/bottom red+ rail.
3) ground both devices to the left/bottom blue- rail.
No luck.. i did start to get a Succesion of motor beeps though, three low in volume but high in pitch beeps. i get that when i disconnect the arduino ground
It acts like it not getting out of sleep mode. You using exact same code as Dan? Also, comment out the two mode type settings at top of loop for now. "digitalwrite(MS1..."
Also, make sure motor wires *never come off when power is to the chip - it can damage the A3967 chip. Not sure why this not kind of protection on it.
yeah, same exact code and wiring as Dan. I get the same clicking after commenting out MS and MS2. i've tried so many things that it just seems like something fundamental.. i have a short video clip of me soldering if by any chance it has something to do with that? it being my first time soldering and all
I still think you have a ground issue. I think your rail is a "split" BB. Try this in any case.
1) Use only lower left side (from your first picture) of power rails. (i.e. keep left of middle line).
2) Stick 12v supply in + rail.
3) Stick 12v ground in - rail.
4) Jump red wire from + rail to ED PWR IN.
5) Jump blk wire from - rail to ED GND (next to pwr in).
6) Jump a ground from Arduino gnd to - rail.
Nah.. no change.. Doesn't look like i have a split board because i set the 12v+ on one end of the power rail and then linked it to the ED (EvilDriver) on the opposite far end, and it still powered up
Jump MS1 and MS2 to ground and see if you can get full step going. If not, then I am out of ideas. Either bad motor, bad board, or some bad wire somewhere.
Thanks though im going to buy a new driver and motor, and if that doesn't work, Then its me messing up somewhere. If so, ill just use the extra parts in another project thanks
Try increasing the delay in between steps. It sounds like a common problem when you're stepping faster than the motor can handle, it doesn't move, but buzzes.
Your right. Probably needs to increase sleep time to ~1 ms. I am also running into some strange behavior that is not really reproducable at will. Many times setting ms1 and ms2 low does not work. It "sticks" at a higher step rate. I then need to pull both to ground to get it "unstuck". Sometimes it works fine - for awhile. My Fez mcu has 3.3v pins. I also tried shorting the 3/5 volt jumper with no more luck. Seems very sensitive to levels on mcu. Or I shorted some resistor or something.
Member183228:
Hard to say. Could you post a picture of your setup? I just got mine working with a FEZ and seems to work good. Wonder if your wires from the motor are mixed up. Do you have Yellow-Blue on left and Green-Red on other?
oh thanks for helping, i posted some photos here http://www.flickr.com/photos/55011272@N02/
i tried so many things i was starting to think maybe its my solder points? It being the first thing i've soldered and all. they seem good though. yes i have Blue-Yellow left and Green-red on the right, and have tried everyother combination as well, in despiration of course. The motor does lock when the powers on... which i read is good? The motor also gets hot and i can feel it clicking in response to Dans Code when he turns Sleep from High- low -high.
cant get it too work for the life of me. i set it up like http://danthompsonsblog.blogspot.com/2010/05/easydriver-42-tutorial.html - The only thing the motor responds to is when SLEEP is changed from low to high, and thats a dull hum at best. sigh any ideas?
What is the difference between Enable and Sleep pins?
Does anyone have GCC code for an atmega48/88/168?
I do not have an Arduino.
Thanks
Hi i just created a driver that can be used with the fezz. You can download it here.
http://www.fezzer.com/project/214/easystepperdriver/
Can I drive a 5V stepper with this?
I'm having a problem where my motor simply jitters back and forth instead of producing rotation, i am not getting any current through A, have I fried something or am I just being stupid in my setup?
Not quite sure what you mean by not running any current through A. You need to have a four-wire (or other, wired as bi-polar) motor properly connected to the four motor outputs of the EasyDriver. Depending upon the step that you're on, you may not get any current through the A coil or the B coil, if you were to measure the current with a current meter. If you tie your STEP and DIR pins low and power it up, the motor should be locked and not twitching at all.
Got mine this morning. It works great and the documentation is great too. Is it normal for the STEP input to draw 130mA at 5V though?
No, that is not normal at all. As you found out, something is wrong with your ED. There seems to be some sort of failure mode (Allegro thinks it could be ESD or some over-voltage damage after the parts leave their factory) where the STEP or DIR inputs draw very significant amounts of current until they are rendered inoperative. I have not been able to duplicate the problem in very extensive testing.
UMMmm Looks like the step input may be faulty,<br />
I had one running for 30 min. from a signal generator and it has now stopped.<br />
<br />
Checked the step input, and it is at 1.5 volts instead of 5V (foldback limited)<br />
<br />
Disconnect the step input, the output from Function Gen goes back to 5.<br />
<br />
Not a good sign!
I made some <a href="http://hobby-electrons.sourceforge.net/modules/easy-driver/">notes with photos</a> on testing the module that I hope might help people wiring it up for the first time.<br /> <br /> STEP still draws a lot of current even though the datasheet says it should draw < 1�A. Is it something I've done wrong?
I have a Sherline milling machine and I believe the best option for stepper motors is Sherline part number 67130. It's a NEMA 23 stepper with dual shafts with voltage rating of 3.2V. I see the ED is 7V-30V. Does this mean I can't use the ED with this stepper motor? Or does the "adjustable current control" take care of this?<br />
<br />
http://www.sherlinedirect.com/index.cfm?fuseaction=product.display&Product_ID=751<br />
<br />
Thanks.
The ED get extremely hot for me, burning my fingers to the touch and stinky, at just 12v 500mah.<br />
<br />
BTW, as others have mentioned, they are very easy to blow with excess voltage. I tried pumping 24v / 3a divided between 3 ED's and one of them blew in a minute without anything unusual, steppers never disconnected.
Umm. "The higher the voltage, the higher the torque." ?
That's not really correct now is it.
The current defines the torque, and current is set by the current limiter.
The voltage however defines the velocity the steps are done at. The higher the voltage, the higher max step-rate. Current, speed and torque are linked though.
I thought with a chopper drive, the higher the voltage will keep the torque high at a higher rpm,<br />
<br />
the torque curves I've looked at for steppers show increased bipolar torque at higher rpms with higher voltage.
I can't seem to get this thing working. I've hooked it up to an arduino as suggested in other posts. With an external power supply of 12v. The stepper motor simply jitters back and forth. All 4 variations of the MS control pins result in jittering.
When I looked at the outputs on an o-scope I noticed that the wave forms didn't correspond to those listed on the datasheet for the A3967.
Any suggestions?
I just fixed the same problem, I had a tiny tiny tiny wire connecting between two of the motor wires between the solder points on the EasyDriver, now it's working great!
Is this board, automatically set for 1/8 step mode?
Do I need to put MS1 and MS2 to pulldowns to achieve FULL step mode?
Yes, if you don't do anything to the MS1 and MS2 pins, it will default to 1/8th microstep mode.
Setting Ms1 and Ms2 to LOW is for full stepping, make sure your microsecond delay isn't too low or it will just make noise, try 800 or so at Full step.
MS1=L MS2=L Full Step
MS1=H MS2=L 1/2 Step
MS1=L MS2=H 1/4 Step
MS1=H MS2=H 1/8 Step
Thanks for the info, I just tied them to ground, seemed to work... another question for the sparkfun guys: on the current revision, 4.3:
is the silkscreen for min and max backwards?
Yes, v4.3 has the MIN and MAX labels reversed.
This board is the link between an Arduino and a Stepper Motor. The interface is simple but powerful and will work great in any project.
For those interested in a Homebrew CnC machine project using this or want simplified code for Arduino + Easy Driver + 2 button forward/reverse control visit:
http://currentamps.com/projects/2-button-stepper-motor-control
Thank You Sparkfun!
Could u tell me when I(we) would have a chance to order them again??
Thank YOU!!!!!
They are in production right now. Give us a few days.
These things are notoriously easy to fry. I'm almost afraid to breadboard assemble these as connection problems may easily lead to the chip malfunction. Invest into good wire terminals for connecting stepper motors.
To save I/O pins, use manual switches, connecting 5v output to MS1 and MS2 (microstepping). For most applications you're not going to be changing it half way though code execution anyway. That way you'll end up with 4 pins going to the microcontroller - sleep, direction, step and common ground. You can have 6 stepper motors running off one Duemilenove.
If the motors are going to be on all the time (and if the power supply can handle it), you can sacrifice the "sleep" pin as well, putting a switch instead. That way you'll have a maximum of 9 steppers per Duemilenove.
Jade, I've done a lot of testing myself with a number of EasyDrivers, and I have not had an easy time frying them.
In one test, I applied 12V, and connected/disconnected the stepper motor (while powered) over 1000 times. The ED was fine.
However, at 24V, it took about 10 disconnect/reconnect cycles before the chip blew.
Some people have reported destroying their EDs through wiring mistakes or over voltages. But not many as a percentage of the total sold.
Took me a week to fry my first 4 in a custom made CNC machine. As I discovered later, the issue had less to do with me disconnecting the motors and more with 12V bleeding into the 5V logic supply. The blame is entirely on me. I have improved my controller design and made it modular, able to test one easydriver at a time.<br />
<br />
http://img808.imageshack.us/i/easydriver.jpg/<br />
<br />
My advise to come out of the failed experiment: "whenever possible, experiment with one component at a time".<br />
<br />
Also, I'm powering 4 easydriver chips, 1 arduino and 4 stepper motors off a single 12V, 2A power supply. When turning the whole rig on, the initial drop in current causes the arduino board to reset. The reset, in turn, causes the easydrivers to reset and the whole thing gets thrown into an infinite loop. The solution is either a good power supply (mine's a cheap wall brick), or filtering caps in excess of 400uF on the arduino supply line pass the voltage regulator (which in my case is a generic LM7805 going into arduino's 5V).
Just a quick check about my facts (or muppetry) before purchase.
This motor is ok right?
http://www.slidesandballscrews.com/sy35st360704b-p-367.html?cPath=45_101
would this board be able to handle my 3v/4Amp stepper motor or would this blow the chip?
You will have no problem with your motor. The only important spec (within reason) is the current. Since this driver can only put out 750mA, and your motor can handle 4A, not only will it be impossible to hurt your motor, but it won't even come close to attaining its max speed and torque. It will probably work OK, but to get the most out of your motor you need a much beefier stepper driver.
That might be pushing it a little bit
Ah... so I have failed and now have a dead duemilanove and easy driver.
as a general question, how do I know how to hook up a given 4 wire stepper motor to this board ?
I can test the connection between wires, so that gives me the wires for each coil, [a] [b], but .. does the orientation matter ? This still leaves open 4 possible writings ( 2 directions x 2 coils ).
Whatever I hooked up worked for the default largest step size, but made weird noises when I tried to turn on half stepping. I wondered if orientation mattered, and how to test for this ?
Here's a helpful tutorial I wrote for you CNC fans.
3 EasyDrivers, 3 NEMA 17s, and a Duemilanova are all you need to do the basic wiring for a CNC machine.
http://www.instructables.com/id/How-to-wire-an-arduino-based-3-axis-CNC-machine/
Will you ever be getting the EasyDriverQuad? It looks brilliant and would make it simpler for a lot of robotic projects
We'll look into it
I just wanted to let you know that I managed to drive a 4-phase 5-wire unipolar stepper using an easy driver. The connection is actually incredibly simple. Connect the four phase wires as you would with a bipolar motor (to the motor outputs on the EasyDriver chip) and then connect the 5th wire (COM) to the voltage supply (the same one driving the EasyDriver, i.e. M+).
I've posted an Arduino Tutorial with sample code here for those who are interested:
http://danthompsonsblog.blogspot.com/2010/05/easydriver-42-tutorial.html
This board looks like it's awesome. I cant wait till I get mine.
Question though: Can the A3967 be swapped out for a driver that supports higher amps per phase? I'm looking for upwards of 2.5Amps. Is the A3977 or A3979 a reasonable replacement?
Reggie, you can't easily swap driver chips on this board for more current. There aren't any pin-compatible driver chips (or I would have used them in the design) and this board is not set up to get rid of the kind of heat a 2.5A driver chip will generate.
But stay tuned. A new board is in the works that should suit you nicely.
3977 is what is banded around on most CNC forums but as for a straight swap a more technical person will have to say it that is possible
Hi
I have two sparkfun motors with their two easydriver wired to an arduino.
When I try to make the two motors work at the same time it's not working correctly. I can't find why.
Someone knows?
thank you
check
http://forum.sparkfun.com/viewtopic.php?f=6&t=21381
According to the schematic, there's a jumper on the board that's bridged by default so that the motor power (7 to 30 volts) is used to power the chip, too. As this jumper is not present (the point is just connected with a PCB track) is it possible to cut this track on the PCB to separate the power supplies? I have my own source of 5volts, so there's little point in feeding a much higher voltage through the onboard regulator and having it heat up. Where on the board would I need to cut?
Yup. There is a little piece of copper between the two pads of JP1 (schematic)/APWR (board). This is the jumper located directly between the +5V pin and the SLP pin.
Cut that trace and apply your own 5V (or 3.3V) on JP4 (+5V/GND) and you will be able to power the board on your own. Note that the voltage regulator is still powered, but nothing is taking any current from it.
Oh of course! Why did I not think about the connector labelled "apwr". Shoulda been obvious. I think I disregarded it 'cause it looked like an open jumper, didn't notice the tiny copper bridge joining the pads :P
Thanks for the quick reply, really appreciate that :-)
Just a quick note to say I received a couple of boards a few weeks ago and they're great.
Mounting Holes:
I got v4.3 boards and they have two mounting holes - as requested by others.
Picking Motors:
Due to budgetary constraints... I've ripped steppers out of laser printers. I've paid little or no attention to the ratings and they've worked very well indeed. YMMV.
Obviously, having the extra pins broken out is very useful.
I've a long way to go with my project but it's been really helped by the new boards. Thanks Brian and Sparkfun.
[m]
i was wondering how to tell if the driver has died,on me. it dose not want to turn the stepper any more it just kinda jitters around,
Any ETA on the next set of boards? Are they in the queue to be made, or is this something that gets batched up and hence will wait for a while...
Just received two new boards... v4.3 - four.point.THREE
What's changed?
[m]
The only change between 4.2 and 4.3 was the addition of the mounting holes. (And that required a little re-routing of the board, but nothing that even changed any component locations.)
I'm using this board to drive 6-wire 1.3A unipolar stepper motors in a bipolar configuration(center-taps unused) at 12V and it works great.
I noticed there are two large holes in the boards being shipped that aren't pictured here. It would be -really- nice if these were aligned with the chip even if diagonally to facilitate the use of a small heatsink.The chip doesn't 'need' one due to thermal limiting but it does get hot at 650mA and I'd like it to stay cooler.
A few other changes I'd find personally useful are moving MS2, Enable, and Reset to the bottom of the board so MS1 & MS2 are together, and keeping them all out of sane reach of the motor/supply voltages. In my mind it just makes more sense to have all of the unregulated voltages on one side and the other be the logic interface.
Yes, I hope they can get the pictures updated with the holes. Those were added to help people hold down the board. I had to move things around a bit in layout in order to fit them in where they are. Without changing the form factor, it would be difficult to move them any other place.
I agree that they could be better moved to support a heatsink, and moving the pins around as you state would be good too. However, I didn't want to go to a four layer board or really narrow traces, and I needed to maximize the copper pour for heat sinking. Moving those pins around would need to make the board bigger.
I can't get this driver to work in anything other than 1/8 step mode (default with nothing connected to MS1 and MS2). I connected two digital output pins on my Arduino to MS1 and MS2. I tried setting them both low for full steps, that didn't work; there was some beeping and no movement. The same happened with every other combination.
Any tips?
If you tie both MS1 and MS2 low, it should go into full step mode. At least mine do when I do this . . .
The problem was actually the code. I used the code in the Portuguese Arduino Tutorial. It has a 100 microsecond delay for the step, this was too short of a timeframe for the motor to take a full step. I set it to 800 microseconds and it works fine. It probably would be fine set lower than 800; i'll see what the lowest I can set it to and that will be my lower limit for how fast I can make the motor turn at full step mode.
I've been looking around, but haven't been able to find any numbers on how microstepping effects the torque of a stepper motor. I'm going to do some testing but it'd be nice if someone knew some numbers, I imagine its more complicated than 1/4 stepping = 1/4 torque, 1/8 stepping = 1/8 torque, etc., but maybe not.
Thanks in advance.
It doesn't make all that much difference in total torque. I'm sure there is some small amount of reduction, but it won't be much. This is true as long as you have the current adjustment pot set low enough that the driver is fully chopping.
Is there a way to use this board with a unipolar stepper?
Sorry Kurt. This one will only work with bipolar motors (or 6 or 8 wire motors wired in bi-polar mode).
so, would you need 3 of these to control 3 servo's?
stepper motor* sorry.
Yup. One EasyDriver per stepper you want to control.
Since I went to tiny stepper motors by now, there seems to be another question regarding the output current.
Is there any way to add a jumper in order to change the Rs for the PWM control to allow switching to 1 - 188 mA output current?
Obviously, I have no idea how much a jumper + resistor adds to the production costs, but that would allow people to use all those miniature steppers ripped out of old CDROM drives or stuff like that.
Anyway, right now I am trying to locate Rs to switch it out for a higher value resistor. If there is something obvious, that makes it much easier to adjust the current range, just let me know...
Hi happycustomer0815,
May I ask what is your source for tiny stepper motors? I've been able to find NEMA 8 size, which would fit my needs, but they are either ridiculously expensive (e.g. Lin Engineering) or they are those floppy-drive style, which don't have enough resolution. Thanks!
This is a really good idea. I will integrate it into the next version of the EasyDriver, whenever that is. For now, you could remove the .75 ohm resistors and replace them with .32 ohm resistors. That would give you a maximum current (When Vref = 5V) of about 200mA. And you could go down from there to about 40mA.
Hi, does it work with 3,3V instead of 5V pulses ?
Tanks
There is a jumper (SJ2) that need to be closed to use 3.3V. Then, it should work with 3.3V as well.
According to the driver's datasheet, logic levels are 0.7*VCC for high.
hello, how can I know which is SJ2 in the board? supposing the label "3/5v" in board's left bottom corner, or there is a drawing with the layout somewhere showing it?
Yes. It is at the bottom left, labeled 3/5v.
just for people who buy the motor and the driver ive made a post on my blog for creating a surveilance system using the motor http://garagedeveloper.wordpress.com/2009/12/05/the-diy-surveillance-system-using-a-webcam-part-1/ . all is open source with code so :) so have fun and thanks to spark fun :)
I second the desire to add mounting holes to the board. What do people normally do, mount the breadboard to the case? I was thinking of gluing the A3967 chip to a heat sink and attaching that to a metal case. Otherwise, its silicone glue i guess...
I've seen two non-breadboard mounting methods.
1) Build a simple daughter board with vertical female sockets for the ED. The pins then provide the mechanical connection.
2) Place the ED on a non-conductive surface like wood or plastic. Solder wires to the holes you need to use. Clamp a small piece of aluminum over the driver chip and screw down with screws to the base material. The pressure on the chip provides the mechanical connection, and the aluminum provides a heatsink.
Just got mine today and it works great! It's nice to be able to disable, sleep, and change the step resolution through software with my Arduino!
Excellent work guys. Thanks alot!
These boards are very nice! There's only one thing I am missing:
For people, who do have their own boards, a "regular" mount option with stand-offs would most likely be worth gold.
On the breadboard it works like a charm, but mounting it somewhere in a project box is really painful right now.
Anyway, thanks for the great board. Much better than v3.1.
yeeeeeeeeeeesssss!! I love you!!
finally, what's the difference between previous version v3.1 ???
See the Version Notes section at http://schmalzhaus.com/EasyDriver/
Oh ... and great work, Brian, on updating this board and releasing it to the public. It's a nice improvement from v.3!
Thanks so much! Report back with how well the new version works for you - I know a lot of folks have wanted all those signals broken out.
Also note that there is now a power LED, and you can see it from the front of the board, and even a little bit from the back of the board too! (Just in case people mount these where you can't see the front.)
I see you have this rated to 30V (the upper limit for the A3967), but you only have a 25V cap on the board (and you shouldn't run them at the upper limit anyway). I'd hesitate to use more than 20V or so myself because of that, but your mileage may, of course, vary.
I love that we have extremely intelligent and quick to post customers! We posted this product at 10:08AM. It took us 24 minutes before we looked like a fool. Not a bad day.
You are correct. Let's just call these 'special edition' EasyDriver boards. We are currently fixing the assembly sheets (my fault) and loading the correct 47uF/35V cap.
I noticed because I did the same thing myself on a custom A3967 board, though I knew it would be OK since it was a 12V motor anyway. :) In reality, ~20V is going to cover 90% of the motors you're likely to use with this board anyway (so I still ordered one of these just to try it out). It's harder than some people might think to find a good motor for this chip, though, given the limits of 150-750mA and 7-30V ... I had to dig around a lot, particularly since there aren't 100 online sources of stepper motors out there (and the ones you do find rarely post all the specs). Thankfully the motor you stock (related products below) is compatible (330mA and 12V).
I've had the opposite experience with finding motors - I completely ignore the specs of the motor (for the most part) and just throw them all at the EasyDriver. I've found that this little chip can drive the smallest AND the largest motors I throw at it. In fact, I have some pretty big motors (3Amp) on my desktop CNC router, and the ED had no problem driving them. Now, it didn't drive them at maximum speed or torque, but it was more than enough for my Frost Bot application. The only thing it can't do is 5-wire motors. With many of the motors that I use (including the one SparkFun sells) the resistance of the motor self-limits the current, and so you have to turn DOWN the current limit pot in order to get good microstepping. But I am continually impressed with the wide variety of motors that it will run just fine.