Feedback wanted for single access GRBL shield

Making a single axis grbl shield for arduino, you can use jumpers to set which axis you want to use, and microstepping jumpers for microstepping. See anything glaringly wrong?

[i.imgur.com] (schematic)
[i.imgur.com] (board)

Thanks!
Goopy

Three STEP signal lines for one stepper? That's odd. Also, there's no need for a reset switch. And you might want two endstops per stepper, one for each end of the axis.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

I think he may want to have some bus setup like idc cables that would be chained from one board to the next and perhaps still have some sort of a choice in which line is step for the current board. But that could lead mishaps like have step on this board and associated dir on another board

I did something like standalone pololu carriers, in case you want that and willing to make your own cables and sorts, feel free to try out this version. The layout is single sided, has generous spaces and tracks, sort of made specifically to be easily manufactured in diy environment.

Well the idea is that you would change the step and dir jumpers to match the axis your gcode is wanting instead of having to change the gcode.

The gcode just knows axis as X/Y/Z/E. The software in arduino has to be told which pin numbers correspond to each axis (step/dir/en). Its easy to change those numbers then (instead of jumpers).

This is intended for GRBL which doesn't use arduino's bootloader, so changing the pins would require writing the firmware through the icsp port not something everyone can do. But maybe I should switch to solder jumpers to save space / time / cost.

Should all three ms pins of the driver go through the pulldown resistor? I notice ramps only does it to ms1

Edited 1 time(s). Last edit at 05/25/2014 06:33PM by goopyplastic.

The bootloader isn't involved in firmware operations at all. Firmware works the same way regardless of which bootloader ist there or wether there's a bootloader at all.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY