Driving the SLA7078MR Using an atmel chip of course

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I have the chip on the breadboard ready to test but I am not clear on the timing diagram in the datasheet (attached SLA7070 page.pdf)

To reset the chip the reset goes high for 2us and then low for a minimum of 5us before any signals from the clock or CW/CCW, M1,M2,M3 ?

The clock can be either high or low does not matter?
M1,M2,M3 and CW/CCW can be high or low or set to any of the various modes?

Depending on the mode set of M1,M2,M3 a step consists of a clock pulse High(2us) low(2us) that has to be complete within 4us?

Can you change modes on the fly during stepping as the gecko drivers do (they micro step at 10 micro steps and go to full step automatically)

I just don't understand the CW/CCW and M1,M2,M3 timing.
Also is M0 show only the half step positions (high level) and full step positions (low level) is this used for feedback that the chip has indeed communicating and stepping?

That should be enough questions for the moment, then I can go ahead and give it a try.


Is there anything connected to the sense A and sense B pins? As I understand it the current is set by the REF pin and a voltage of 0.04V to 0.4V Does this mean you need a resistor ladder or DAC to microstep by stepping the voltage to the REF pin up in increments of 0.024V if you are in "4W1-2 Phase(1/16 Step" I thought this was suppose to be a simple stepper chip but I am very confused at the moment.


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I finally got it, runs great.
I want to thank Dave at Hobbycnc.com for his help on this. Whthout this kind of help I may have given up on trying.
In his first response to my ask for help he wrote this:

email said...
Mark, Why is this important? Regards, Dave Rigotti HobbyCNC.com

Then after a very long email describing why it was important I received this.

Email said...

Probably best to ask this in an open CNC forum. Your questions are beyond the normal scope of support.
Thank You for understanding

So I decided to continue trying to figure it out on my own. Now I can get on to other things and know if I ever need to use the SLA series chips I will understand how to use them.
Running at 1/16th steps (3,200 steps per revolution) Amazing as there is no load and no problem with resonence at 11 KHZ step rate about 206 rpm


Oh the problem was the adaptor board, two of the pins were not connected to the header pins, I did have it connected correctly, just my soldering skill was bad.

The next step is to figure out how Gecko drives change from microstepping to full stepping on the fly, I have not yet got it through my head the algorythm one would use to acheave this but as yet I have only thought about it in the abstract. Soon I may apply some thought to it.