![]() It also sets these pins as outputs, and puts them to the proper logic levels to begin driving the motor. The first section of the sketch defines all of the pin connections between the Arduino and the Big Easy Driver. The connections between the Big Easy Driver and motor are as follows.īig Easy Driver Demo Sketch Download (ZIP) In our example, we are using a 4-coil motor. There is no polarity on the coils, so you don't need to worry about plugging in a coil backwards on the board. The first coil pair should be plugged into Coil A+ and Coil A-, while the second coil pair plugs into Coil B+ and Coil B. Once you have determined the coil wire pairs, you will need to attach them to the Big Easy Driver. Repeat for the second group of three wires. ![]() Once the three wires for one coil have been determined, find two of the three that show the highest resistance between them. Two wires should show some resistance between them and the first wire picked, while the other three will show no connection at all. Pick one wire, and test this against all other wires. ![]() The remaining two wires should show similar resistance between the two of them.įor a 6-wire motor, you will need to determine which of three the wires go together for one coil. Whichever wire shows the lowest resistance against the first wire is the pair mate. However, if you are using a 4-wire or 6-wire stepper motor, it is still possible to determine the coil wire pairs without the datasheet.įor a 4-wire motor, take one wire and check its resistance against each of the three remaining wires. Changes in state from HIGH to LOW or LOW to HIGH only take effect on the next rising edge of the STEP command.Ĭoil wire diagram from the datasheet for our 68 oz.in, NEMA -17 Stepper Motor. This pin determines the direction of motor rotation. Direction and size of step is controlled by DIR and MSx pin settings.ĭIR: Logic Input. Any transition on this pin from LOW to HIGH will trigger the motor to step forward one step. The IC will return the FETs to the home microstepping position found in the diagrams on page 14 of the datasheet upon receiving a HIGH signal on this pin. When switching this pin to HIGH to wake up the IC, allow 1 ms of delay before sending a STEP signal. When set to LOW, the A4988 enters sleep mode, and disables functionality of the FETs, internal current regulator and charge pump. This must be set HIGH to enable functionality of the motor driver. The translator is set to the Home state as well. When set LOW, all STEP commands are ignored and all FET functionality is turned off. See truth table below for HIGH/LOW functionality. Microstep Select 3 has a pull-up resistance of 20 kOhms. Microstep Select 2 has a pull-up resistance of 20 kOhms. Microstep Select 1 has a pull-up resistance of 20 kOhms. If set to LOW, all FETs will be enabled, allowing motor control. If set to HIGH, the FETs will be disabled, and the IC will not drive the motor. Enables the FET functionality within the motor driver. Other half of connection point for bi-polar stepper motor coil B.ĮNABLE: Logic Input. Half of connection point for bi-polar stepper motor coil B.Ĭoil B-: DMOS Full Bridge 2 Output A. Other half of connection point for bi-polar stepper motor coil A.Ĭoil B+: DMOS Full Bridge 2 Output B. Half of connection point for bi-polar stepper motor coil A.Ĭoil A-: DMOS Full Bridge 1 Output A. Board Top PinsĬoil A+: DMOS Full Bridge 1 Output B. Several pins of the A4988 IC are broken out on the Big Easy Driver, allowing direct connection to a bi-polar stepper motor, as well as a microcontroller. Functionality between the two sets does not change. You can use whichever pin connections work best for your project. The secondary connection points are closest to the edge of the board, and are spaced to fit 2-pin screw terminals. The first, which are the pins closest to the center of the board, are spaced out to fit standard 0.1" headers. Each pin present on the board has two connection points. The Big Easy Driver is designed around the Allegro A4988 motor driver.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |