Unlimited DIR outputs with single DIR line January 16, 2018 11:09AM |
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Re: Unlimited DIR outputs with single DIR line January 16, 2018 03:31PM |
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Re: Unlimited DIR outputs with single DIR line January 16, 2018 03:38PM |
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Re: Unlimited DIR outputs with single DIR line January 16, 2018 05:07PM |
Registered: 7 years ago Posts: 270 |
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dc42
You don't need anything that complicated, you can just feed a single DIR line to all the stepper motors. With standard stepper drivers, the DIR signal only has to be stable from a little while before the rising edge ot STEP until a little while after.
Using a common DIR signal in this way does reduce the maximum step rate a little, because you have to set DIR one way, a little, pulse STEP to all the stepper drivers that need to turn that way, then set DIR the other way and pulse all the stepper drivers that need to go that way. You need a delay between each pair of steps, although you can overlap some of the delays with setting STEP back to LOW.
Re: Unlimited DIR outputs with single DIR line January 17, 2018 02:55AM |
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Re: Unlimited DIR outputs with single DIR line January 17, 2018 03:16AM |
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Re: Unlimited DIR outputs with single DIR line January 17, 2018 10:23AM |
Registered: 7 years ago Posts: 270 |
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Attention microPlyer only works perfectly with a stable STEP frequency. Do not use the dedge option if the STEP signal does not have a 50% duty cycle
Re: Unlimited DIR outputs with single DIR line January 17, 2018 06:00PM |
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Re: Unlimited DIR outputs with single DIR line January 17, 2018 09:54PM |
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Re: Unlimited DIR outputs with single DIR line January 18, 2018 03:35AM |
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newbob
It occurred to me that with common DIR line technique, when going diagonally (while one stepper dir line is high and other's low), extruder will move in a staircase like pattern. Microsteping will cover it up but it may be an issue, in corner cases, when printer lacks resolution and is moving slowly.