NOTE: This page describes Gcode supported by TinyG in firmware versions 0.95 and later

See also:

• Feedhold and Cycle Start (Pause and Resume)
• Homing and Limits

TinyG implements the NIST RS274v3/ngc dialect of Gcode. We try to adhere as closely as possible to the NIST Gcode and LinuxCNC Gcode specifications:

• Kramer's NIST RS274NGCv3 Gcode Specification
• LinuxCNC Gcode Specification
  

This table summarizes Gcode supported. axes means one or more of X,Y,Z,A,B,C.

Some of the more complicated commands are described here. Much of this is shamelessly cribbed from the LinuxCNC Gcode pages

Currently the only G10 command supported is G10 L2, which is used to set coordinate offsets. Use Pn to select coordinate system 1-6 (G54 - G59, respectively), and one or more axis value to set the offset for that axis. The format is:

G10 L2 P1 X0 Y0 Z0 A0 B0 C0  - set G54 offsets to zero, making G54 act as persistent absolute coordinates

G28 (and G30) will move the machine to the absolute coordinates set in G28.1 (G30.1), optionally through an intermediate point. Movement will occur at the traverse rate (G0 rate). Axes that are not specified are ignored (not moved). The axis value is the intermediate point for that axis.

Format is:

G28 X0 Y0 Z0 A0 B0 C0

Example of use:

• Go to an arbitrary position, e.g. G0 x100 y100
• Send G28.1 - This will "remember" the absolute position. This position remains constant regardless of what coordinate system is in effect.
• Then go to a different place, e.g. G0 x50 y50
• Send G28 - The machine will return to x100 y100

Example:

• Go back to X0Y0
• Send G91 G28 Z10 - this will move to x100 y100. The tool will initially lift z by 10 mm (or inches); G91 is used to set relative mode for this command.

TinyG supports exact path mode (G61) and exact stop mode (G61.1). G64 is recognized, but is treated as exact path mode. In exact stop mode motion will stop between each Gcode block. In exact path mode the exact path is followed (i.e. corners are not rounded). The velocity at the points joining 2 blocks is controlled to keep the change in direction between the blocks within centripetal acceleration limit set by $JA. Please see here for an explanation.

program END (M2, M30) performs the following actions:

• Axis offsets are set to G92.1 CANCEL offsets
• Set default coordinate system (uses $gco)
• Selected plane is set to default plane ($gpl)
• Distance mode is set to MODE_ABSOLUTE (like G90)
• Feed rate mode is set to UNITS_PER_MINUTE (like G94)
• The spindle is stopped (like M5)
• Motion mode is canceled like G80 (not set to G1)
• Coolant is turned off (like M9)
• Default INCHES or MM units mode is restored ($gun)

Reports the current target position.

Example:

M114

X:100.0000 Y:0.0000 Z:0.0000 A:0.0000 B:0.0000 C:0.0000

Reports the firmware, version and capabilities as many other controllers do. This allows Gcode generating software connected to an initially unknown controller to automatically detect it and adapt itself accordingly. Gcode generating software can then provide a "Plug-and-Play" experience to the user.

Example:

M115

FIRMWARE_NAME:TinyG, FIRMWARE_URL:https%3A//github.com/synthetos/TinyG, FIRMWARE_VERSION:0.97, FIRMWARE_BUILD:440.21, HARDWARE_PLATFORM:1.00, HARDWARE_VERSION:8.00

Sets the jerk of one or more axes transiently. Axis jerk rates are given in units per second³ in order to remain compatible to analogous M201 commands on other controllers. The jerk rates are internally converted to TinyG's km per minute³ rate. Note, $xjm, $yjm etc. remain unaffected by the transient setting.

Example:

M201.3 X90000 Z10000

Watch a video of how this is useful for the OpenPnP software:

https://youtu.be/6SBDApObbz0

Some Gcode generating application (e.g. OpenPnP) need to interact in real-time with the machine. One example: A camera is moved to a location, then Computer Vision is used. Obviously, the application needs to know when the camera has arrived, before it can take a picture.

M400 blocks all further command processing, until the move buffers have drained. The acknowledgement "tinyg ok>" is only reported once this has happened. The application can therefore synchronize itself efficiently with TinyG.

Example:

G1 X100
M400   ; wait for the move to complete
M114   ; only now report the position

• Comments start with a '(' char or alternately a semicolon ';'
• Comments always terminate the block - i.e. leading or embedded comments are not supported

Valid comment cases       Notes:
G0X10                      - command only - no comment
G0X10 (comment text)       - command with comment
G0X10 (comment text        - it's OK to drop the trailing paren
G0X10 ;comment text        - comment delimited by semicolon (firmware build 378.05 and later)
(comment text)             - there is no command on this line

Invalid comment cases     Notes:
G0X10 comment text         - comment with no separator
N10 (comment) G0X10        - embedded comment. G0X10 will be ignored
(comment) G0X10            - leading comment. G0X10 will be ignored
G0X10 #comment             - invalid comment separator