Need Help!- Picstep stepper current adjustment

[EUnit]

Hey guys. I'm working on a PicStep bipolar stepper driver after I found the idea on fromorbit.com. After some research I found that the functional diagram on the Data sheet of the LMD18245T's showed a similar layout in the schematic I thought I'd ad a little more functionality and customization to the driver. First being the Current adjustment.

The schematic off of 'Fromorbit.com' gives you a resistance value for a predetermined amperage output from .1 - 3A (Max) resistors varying from 200k (lowest) to 6.6k (Max Amps)

Now each Driver IC controls one Coil of the stepper therefore needing two for one stepper driver.

Now I was wondering if instead of having a fixed resistor in place for a set Amperage. Would it be possible to combine the RC(3) pins of both IC's with one Trimpot and using a single 500pF cap to control the current equally on both sides without causing interferance?

Attached is my schematic. Its incomplete but feel free to sugest changes and/or improvements I could do. The Microcontroller is programmed to run the driver in full and half-step modes.

[mmcp42]

I suspect not as it is almost certainly measuring the current not just setting it
so unless your motors were identical and under identical load, it wouldn't work

just my 2p worth u understand
YMMV

[EUnit]

Good point. Although bot IC's are running one motor thus the current draw/load should be identical in both coils BUT to be safe I had an Idea dawn on me while reading your post... Instead of having fixed resistors in place of that. I will solder in two jumpers. One for each IC. That way I can still adjust the current for the motors while keeping both IC's separate but with equal calibration at the same time. At least this will give me some versatility when hooking up my steppers.

[James Newton]

You do realize LMD18245T's are $15 a pop?

[Drools]

EUnit, the AVRSTMD.com drivers are based upon the LMD18245T. His design uses a trimpot to adjust the current. (1 per coil)