I have finally conceded to the forums. I am wondering if there is something that I have not been able to dig up or just doing wrong.
I am using a BED on an arduino UNO R3 and everything works just flawlessly EXCEPT 1/16 microstepper. It works just the same as doing 1/8 microstepping. If I use half or quarter steps it seems to work fine, but if I use 1/16 steps it only does 1/8 steps. I have tested the connections to make sure the pin of the arduino has continuity with M3 on the board.
I am using the Accellstepper libraries and just wondering if there is something I dont know that I need to know.
Dave
I thought it might be of importance that I am using a 0.45deg/step motor
The trick for 1/16th microsteps is to make sure that your power supply voltage is high enough, that your motor coil resistance is low enough, and that your current adjustment pot is set low enough. Do you know these parameters for your system? If your power supply is 12V or higher and your coil resistance is about 20 ohms or lower, then try turning your current adjust pot all the way down (measure voltage on TP1 to know which direction is ‘down’) and then slowly ramp it up as you’re running your motor to see if you can get it really smooth.
What happens when you set it to 1/16th (by leaving M1,M2 and M3 all unconnected) and you only get a step every other pulse is that the current limit is not kicking in because your parameters aren’t correct, and so it can’t limit the current to the coil properly.
At least that’s one way it can go wrong. 
*Brian
Thank you Brian I tried what you said and I still have the same problem =(.
I do know that the specs I got for the motor says 2.7 ohms per phase and its a 4 phase. My voltage is 19.6V. When I turn the pot down (mine is backwards) it just comes to a stall and jitters.
Dave
Hmm, OK good. So you’ve tried the obvious stuff.
When you say that the 16 microstep mode doesn’t work - how exactly are you testing it? How does it behave differently than 1/8ht mode?
Another thing to try is to remove all wires from the MS1, MS2 and MS3 inputs on the BED and measure the voltage on each pin. They should all be at 5V. If one of them (MS3 I think) is low, then that would be why you’re not getting 1/16th microstep mode.
*Brian
What I mean is the 16 microstep mode works exactly like its actually 8 microsteps. Since I have a .45 deg/step I get 800 steps per rotation. That means in 16microstep mode I should get 12800 steps per rotation but I am only getting 6400 just like in 8 microstep mode. With 1/8 mode I will need to make a gear reducer and I really would rather just use 1/16 mode and avoid that.
I tested the voltage at MS1 was (5.08V), MS2 was (4.26V) and MS3 was (4.25V) hrmm maybe we are on to something?
While I got you here can you tell me if you know why when I say go the amount of steps to go exactly 360 degrees it doesnt look accurate. Its close but doesnt look dead on. I have not actually measured it precisely yet though.
Thank you again Brian,
Dave
Ok I have hooked up the arduino to the 19V power supply using a 5v voltage regulator and the voltages seem to be more in line. However things just got more confusing for me. I cant even figure out which step mode I am in because if I say go 800 steps in normal step mode it does 4 rotations when it should do 1, and some step modes do not change the steps at all just like the 8th and 16th. I think I am just going to get one of those pololu 32 step drivers. It might be the accelstepper library though I dont know.
Dave
Dave,
That is very strange indeed. Can you post me a link to the stepper motor you are using?
If you set MS1, MS2 and MS3 low (by tying them to ground - i.e. full step mode) and send exactly 800 pulses, you should get 1 revolution. If you get something different than that, then you may not have a .45 degree/step motor. How did you determine the .45 degree/step rating of the motor?
Another thing to try is to not use AccelStep for a while - just send the pulses yourself in your code. That eliminates one variable from the equation.
Your MS2, MS1, MS3 voltages look ok (anything over about 1.5v should be considered “high”).
*Brian
It sounds like you need accurate steps with much higher resolution than 800 steps/rev. If so you should probably look into a geared stepper. This example offers 20000 full steps/rev http://www.stepperonline.com/gear-1001- … -p-36.html