Using the SD Card

The is currently a proposal only.

Overview

The command style is temporary and subject to change. The commands and responses were chosen to in a Grbl style rather than a Marlin type style. This will allow Grbl senders to be used without issues. If a Marlin style is preferred, changes can be made after the system is fully tested.

Commands

$FM

Mount the SD card. This must be done before listing or sending files.

$F

Show all the files. This is recursive and will search all subdirectories. Each file will print like this...

[FILE:\FOO.NC SIZE:29547]

...where \FOO.NC is the filename. including the directory. In this case the directory is the root. The number following the file name is the file size. This is not case sensitive.

There is a filter for valid file types in grbl_sd.cpp

char fileTypes[FILE_TYPE_COUNT][8] = {".NC", ".TXT", ".GCODE"};

There are a few naming restrictions because of how grbl strips out characters. I'll need to post those rules or figure out a way around that. Using line_flags like LINE_FLAG_COMMENT_PARENTHESES might work.

$F=\FOO.NC

Run file \FOO.NC

Note: If in alarm mode command will fail with error 9

Other Actions

Pause/Restart

Just use the normal grbl cycle start and feedhold commands

Stop/Quit a file

Initially this will be Grbl Reset. If that does not work out then $FQ will be added.

Status

I am not sure how to send status. I think adding an optional thing to the ? is probably the best. Maybe a percentage that gets added in when an SD file is running.

<Idle|WPos:195.000,144.000,19.000|Bf:15,128|FS:0.000,0.000|Pn:P|WCO:-195.000,-144.000,-19.000|SD:45.5>

Errors

There will be some sort of state machine type thing to make sure mount, run, unmount, etc do not cause undesirable effects.