Getting Started with the AutoDriver
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The AutoDriver board is designed to be easily integrated into a project, even with multiple boards. Here's a brief tour of the hardware and how to connect it up.
As you can see above, there are several connectors on the board. Let's take them one at a time:
- Communications in - where the SPI, clock, and logic level power enter the board. That can be either from the system CPU or from a prior AutoDriver board. By default, the AutoDriver expects a power supply input here, but that power supply is not the supply to the motors and should not exceed 5V. Designed for a 2x5 .1" shrouded connector, and to be connected by a 2x5 ribbon cable.
- Communications out - SPI, clock, and logic power out to the next AutoDriver. Designed for a 2x5 .1" shrouded connector, and to be connected by a 2x5 ribbon cable.
- Control signal in - metasignals for input and output to and from the AutoDriver. Chip select, optional step clock, and reset inputs come in here, and open-drain busy and error flag signals go back to the previous board. Designed for a 2x3 .1" shrouded header and to be connected by a 2x3 ribbon cable.
- Control signal out - passes the common control signals on to the next AutoDriver. Note that chip select is not passed from one board to the next; obviously we want only one board to be selected at a time. Designed for a 2x3 .1" shrouded header and to be connected by a 2x3 ribbon cable.
- Switch input - the L6470 can accept input from switches to provide for a hard-stop limit switch or a configurable user interrupt. We'll cover that later. Sized for a 3.5mm screw terminal.
- Power input - two connectors with two terminals each for power and ground to make connecting multiple boards to one power supply easy. This is the motor power input and is sized for a 3.5mm screw terminal.
- A and B winding outputs - the L6470 is designed to work with a bipolar stepper motor or a unipolar or universal stepper motor configured as a bipolar. One winding should be connected to each of these terminals, although it doesn't matter which winding connects to which terminal (other than to determine which direction is considered "forward").
- ADC input/potentiometer footprint - this footprint can be populated with a 200k potentiometer to provide for motor supply voltage correction, to ensure a constant drive current across varying supply voltages. Highly optional, but we put the footprint there, just in case.
An Example Connection to a RedBoard
Later in this tutorial, we will show you how to hook up two AutoDriver boards to a RedBoard. For that example, you'll need two AutoDriver Boards along with the following: