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makerbase-mks / MKS-SBASE

MKS SBASE is a powerful 32-bit 3D printer control board with LPC1768. Support Marlin2.0, Smoothieware. Support MKS LCD12864 and MKS TFT Touch Screens（SBASE V1.4 support MKS LCD12864A/MINI12864/LCD2004）. The motherboard integrates 5 DRV8825 axis and it is use software set current, supports wired network for printing and supports firmware update by SD card…
https://www.aliexpress.com/item/32384368763.html?spm=2114.12010612.8148356.13.f6ef39440hYPmP
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What is DRV8825 decay mode used by board? #14

Closed egorse closed 7 years ago

pixel3design-hub commented 8 years ago

If you mean Fast Decay Mode, it's an internal function of the DRV8825. It's a good function badly implemented, even in the original Smoothieware Hardware. It needs diodes in reverse parallel on two channels of the output to stop motor making terrible noise in 1/32 step mode, just because current phase control is generating harmonics and sub harmonics from the 30KHz pulse signal that chip is working on.

Kinda of...

egorse commented 8 years ago

I am on pin 19 - is that low, open or high?

But thanks for prompt reply!

pixel3design-hub commented 8 years ago

Low = slow decay, open = mixed decay, high = fast decay. Internal pulldown and pullup.

egorse commented 8 years ago

I can see that from datasheet - but whats on the PCB/assembly?

tiaanv commented 7 years ago

I second the request. Is the PCB wired to put the DRV8825 in fast decay mode or is is mixed mode? Would not be able to see unless I remove the heatsink which I would not like to do. Listening to it in operation, I think it might be in Mixed mode. Please confirm.

Steamerzone commented 7 years ago

As far as I can measure it, it's running in mixed decay mode. (decay pin is open)

makerbase-mks commented 7 years ago

MKS Sbase's drv8825 all use mixed decay mode.

feket663 commented 7 years ago

Can I use this board with 24 power supply and relativly high inductance stepper motors with low current? Need enable fast decay mode?