Confused/Frustrated, need help with servo shield

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cuthbertsj
Posts: 7
Joined: January 26th, 2018, 1:33 pm

Confused/Frustrated, need help with servo shield

Post by cuthbertsj » May 2nd, 2018, 12:56 pm

Hello all,

So I have been really struggling to get this servo shield to work. I started using the Lucid IDE and kept getting errors so I switched to the ISE. After much effort i managed to get the servo shield to output a PWM. And its beautiful. I have it hooked up to an Oscope and I can watch the pulse width changing, its quite magical. I followed the tutorial for servos using Verilog. the one where the servo should move back and forth.

Where I am getting lost and having issues is, when i actually plug a servo into the servo shield my output signal goes crazy weird. I have talked with my professors and we cannot figure out why it is doing this. Possibly feedback of some kind, really not sure though.

I will atatch pictures of the waveform before and after the servo is plugged in. Any help would be greatly appreciated. I am graduating soon and this is part of my final project. Please help me.

Thank you,
Joe
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MOJO before.PNG
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MOJO After.PNG
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cuthbertsj
Posts: 7
Joined: January 26th, 2018, 1:33 pm

Re: Confused/Frustrated, need help with servo shield

Post by cuthbertsj » May 7th, 2018, 10:59 am

After much trial and error I have determined I need a pulldown resistor. is there a way to do this in the board? or do I need an external resistor?

Thanks,
Joe

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