GRBL + Mega2560 HELP!

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Thread: GRBL + Mega2560 HELP!

  1. #1
    *Registered User* Twiens99's Avatar
    Join Date
    Jan 2019

    Default GRBL + Mega2560 HELP!

    Ok. I've been having this problem for some time now, I've been searching the internet for the solution but I cannot find it.
    My Knowledge is Limited, but my troubleshooting ability has definitely gone up since I ran into a wall!

    So when I Load GRBL onto my Arduino, I know that Pin 13 is supposed to control the EN leg on my pololu Stepper Drivers

    What I would like is for someone else to try this and tell me their results.

    Attached is a picture of my circuit.

    Arduino GND to GND rail
    Arduino 5V to 5V Rail
    10k Resistor to 5V
    D13 - 10k Resistor

    For the Drivers to work I know that the EN leg has to go to 0V
    I can Send G Code through Universal GCode sender. That works. And I can easily look @ settings and other things. Computer says I'm connected.

    Measuring D13 shows 4.92V with the above circuit
    The Drivers will engage the Stepper motors when the EN leg reaches 0V

    I can't get 0V on D13!!!!!!

    What am I doing wrong?

    Please Somebody please help me!


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  2. #2
    Join Date
    Mar 2015

    Default Re: GRBL + Mega2560 HELP!

    I have used the Atmega2560 and TB6600 /TB6560 drivers without any problem. On these drivers, if you just connect the step pin, steppers will work. Also I connect the Arduino step/dir/enable pins directly to the driver pins because these pins are designed to be controlled by a 5 Volt signal.

    I don't have Polulo drivers so I can't test your situation but I have checked the schematic, there are no optocouplers and all pins (except Step) have a 100k pull up or pull down resistor. To get the motor turning, you only need a pulse on the step pin. Just connect the step pin alternating to VCC and GND simply by using a wire and the motor should run!

    If the motor is harder to turn when the enable pin is at 0 Volt, the A+/A- and B+/B- motor wiring are OK, if not, the motor wiring is wrong. Use the multimeter to find the wires that form a coil, the resistance should be very low just a few Ohm. A+/Ai should be connected to one coil, B+/B- to the other coil.

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GRBL + Mega2560 HELP!

GRBL + Mega2560 HELP!