2nd Generation MaslowCNC Controller on GRBL

[Joshua]

@ldocull

You will need the 10nF caps in addition to the level converters. The parallel resistors work with the hall-based encoders that are specific to the motors from the kit. There are noise spikes all over the encoder lines (because the cables are really long, not twisted, and high-impedance) that the Due will pick up due to its speed and i/o sensitivities. Without the caps you will have positioning errors. I struggled with this for a few hours until I busted out the scope and looked. Once the caps were added, no more errors.

@Idocull, I would like to understand this further.

I have a hypothesis that there are positioning errors that come from missed encoder pulses, or falsely detected encoder pulses.

I understand that the speed and sensitivity of the Due highlighted this as an issue. However, I am wondering how likely this is as an issue with the stock Arduino. In your opinion, is it likely that the stock Arduino suffers from this issue? If so, to what extent?

Thanks. I appreciate your effort and expertise.