Drv8834 default stepping mode mistake in documentation

Support Motor controllers/drivers and motors
1

The pololu web page for the DRV8834 carrier (and some posts in this forum) says “M0 is floating by default”. I think this is a mistake, since the data sheet for the DRV8834 (SLVSB19D – FEBRUARY 2012 – REVISED MARCH 2015) on page 4 says “Internal pulldown.” In other words, if you don’t connect M0 and M1, the chip has micro stepping mode of “full.”

I could be wrong, maybe TI’s data sheet is wrong. Now that I think about it, the data sheet also says M0 is tri-state. So if it were internally pulled down, it would be impossible to put it in a floating state? Thus the TI data sheet must be in error, and should not say that it has an internal pulldown.

2

Hello.

I suspect the DRV8834 chip has an internal pull-up and pull-down on the M0 pin, essentially creating a voltage divider. This would allow it to reliably determine if it is being driven high or low or neither. I measured one here and got a voltage of ~1.5V while it was not connected to anything, so it is considered floating in the respect that it is between the input low voltage (0.7V) and input high voltage (2V) specifications in the datasheet.

Brandon