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MDD3A stepper code example question

PostPosted: Thu May 23, 2019 6:14 am
by mbewley59
I'm new here and just picked up the mdd3a driver. I'm trying to understand the instructions at the beginning of the StepperFullDrive example, where it states: '// Connect 4 pin on SHIELD-2AMOTOR to "Signed Magnitude" mode'. I assume it's talking about setting up the 4 output pins to connect the driver, but it's clearly more than that. I see no jumpers or pin labeled as such. This is one of the examples in the Cytron 3A Motor Driver Shield library I got from Arduino, so maybe it's not even the right library...

Not wanting to fry this driver, I was hoping someone might explain it to me? I'm using an Arduino Nano to run a NEMA 17 stepper with this driver. Thanks in advance.

Re: MDD3A stepper code example question

PostPosted: Sat May 25, 2019 6:31 am
by ober
I think that is meant for Shield-3AMotor as stated. And the Signed Magnitude mode is a method of controlling motor speed and direction with different pin, Speed controlled by PWM pin while Direction controlled by DIR pin.
While for MDD3A, it is not a shield, so the connection from controller to driver is flexible. MDD3A is actually based on discrete MOSFETs H-Bridge, where the true table is as shown in the product page:

And the library is meant that you refer is meant for
Cytron 3A Motor Driver Shield, not for MDD3A :)

Looking at the true table and the connection of stepper motor to MDD3A:
I think is quite straight forward to drive stepper from Arduino, just drive the output pin(Output 1, 2, 3, 4) in sequence accordingly to your wiring connection of stepper motor to MDD3A. Try it. And I don believe you will burn the driver as long as you do not short the output.

Re: MDD3A stepper code example question

PostPosted: Sat May 25, 2019 11:12 am
by mbewley59
Thanks! I'll just look around for another stepper lib, and maybe that will help solve the jitters.