Blog » A4983 on a breadboard
posted on 14 Feb 2011 14:27
The Smoothie project will use the Allegro A4983 chip to drive the stepper motors.
It's a very nice chip, it has 1/16 microstepping, can drive up to 2A, and has the simple step/direction interface.
Most common way to use it is via the Pololu Driver Carrier, but in the case of Smoothie, we want all of the 4 drivers directly on the PCB, so that they can share the heatsink/fan, and also share some components.
Before designing the Smoothie PCB, it's important to be sure how exactly the A4983 works.
Here is a ( successful ) attempt to use a A4983 on a breadboard.
Explanations bellow assume you are already familiar with at least the Pololu board.
Here's how it looks :
And a closer look at the breakout board :
Now that's not very easy to read, so here is the Fritzing version of it :
And the corresponding file.
It works fine : the stepper turns, and makes that nice microstepping sound. Also the potentiometer adjusts the current like in the Pololu board.
A few notes :
- The dir pin is connected to +5V so it only goes one way, that's just because this is a test, just connect it to an arduino digital output, and you can change directions.
- 3 resistors are missing, if compared to the example in the datasheet. That's because as Smoothie will be USB-powered, we assume the power supply can be trusted. It reduces cost, and gives more free space around the chips ( there need to be no other component around the 4 A4983 so that they can be directly in contact with the heatsink.
That's all for today.
Next step : controlling the current setting of the A4983 with the MCP4331 digital potentiometer.