Big Easy Driver User Manual Doc version 1.2, for BED v1.2 11/04/2012 Brian Schmalz Schmalz Haus LLC www.schmalzhaus.com/BigEasyDriver brian schmalzhaus.com Description The Big Easy Driver (BED) is a major revision of the Easy Driver stepper driver board. The BED takes power and control signals (STEP and DIRECTION) and produces the signals necessary to step a 0A to 2Amp bi-polar stepper motor. The BED uses an Allegro A4983 or A4988 driver chip. Figure 1: Big Easy Driver v1.2 Hook Up The BED has holes for both .100 headers as well as 3.5mm screw terminals. Either or both can be used to connect to the BED however you want. You can put female or male headers in the .100 holes or solder wires directly to the holes. The minimum number of connections to the BED is 7 four stepper wires, Power, Gnd and Step. All others are optional. Note that there are two ground connections one next to the power input, and one next to the step input. Typically these will connect to the power supply ground and the signal ground (from the microcontroller) respectively. Top Edge Connections Motor: Connect the four wires from the motor to the four motor connections on the BED. The two A connections should connect to one coil, and the B connections to the other coil. Power: Connect the power input (+8 to +30V filtered DC) to the M+ connection, and GND from the power supply to the GND connection. Bottom Edge Connections ENABLE: This input is pulled down on the board with a 20K Ohm resistor. You can leave it disconnected, or you can drive it from your microcontroller. When low, the driver chip is enabled and the motor is energized. When high, the driver chip is still enabled, but all of the final motor drive circuits are disabled and so no current will flow to the motor. MS1, MS2, MS3: These inputs are all tied high with 20K Ohm resistors. They set the microstep setting. Use the following table to know how to control the microstep settings: MS1 MS2 MS3 Microstep Resolution Excitation Mode L L L Full Step 2 Phase H L L Half Step 1-2 Phase L H L Quarter Step W1-2 Phase H H L Either Step 2W1-2 Phase H H H Sixteenth Step 4W1-2 Phase RST: (Reset) This input is tied high with a 20K Ohm resistor on the BED. If this signal is pulled low, the motor driver circuits are shut off, and the driver is reset. Only when this input is high will the driver chip enable the motor driver circuits and pay attention to the STEP input. SLEEP: This input is tied high with a 20K Ohm resistor on the BED. To put the driver chip into a lower power mode (motor driver circuits shut off, charge pump shut down,