M108 - Break and Continue

control Break out of the current waiting loop


The M108 command requires EMERGENCY_PARSER for full effectiveness. (Otherwise a full queue blocks the parser.)

Some G-code commands cause Marlin to go into a closed loop, waiting indefinitely for a certain state or event. For example, M109 waits for the target temperature to be reached, and M0 waits for an LCD click.

  • In the case of M109, the M108 command stops waiting for the target temperature and continues processing G-code. This may result in “cold extrude” messages. For a full stop use M112.
  • In the case of M0 the M108 command acts like the LCD button, breaking out of M0 and continuing to process the G-code queue.


With both EMERGENCY_PARSER and HOST_KEEPALIVE_FEATURE enabled, hosts will be able to prompt for continuation or cancellation, confirming with M108 and cancelling with M112.




Use M108 as a “Continue” button in your host software.

M0 You're up, mate ; in your G-code file 
M108               ; as your "Continue" button