EEPROM Settings


For in-depth documentation on all of the settings in GRBL and what they mean, visit:

You can make changes to your machine’s settings by changing the values in your EEPROM. These are settings that will persist even after you power off your machine and control things like the maximum speed, the acceleration, steps per mm, and more.

Start by sending the command “$$” to your machine. Your console will give you a list of values.


$0=10Step pulse time [microseconds]
$1=100Step idle delay [milliseconds]
$2=1Step pulse invert [mask]
$3=5Step direction invert [mask]
$4=1Invert step enable pin [boolean]
$5=0Invert limit pins [boolean]
$6=0Invert probe pin [boolean]
$10=1Status report options [mask]
$11=0.010Junction deviation [millimeters]
$12=0.002Arc tolerance [millimeters]
$13=0Report in inches [boolean]
$20=0Soft limits enable [boolean]
$21=0Hard limits enable [boolean]
$22=0Homing cycle enable [boolean]
$23=0Homing direction invert [mask]
$24=25.000Homing locate feed rate [mm/min]
$25 = 500.000Homing search seek rate [mm/min]
$26 = 250Homing switch debounce delay [milliseconds]
$27 = 1.000Homing switch pull-off distance [millimeters]
$30 = 30000Maximum spindle speed [RPM]
$31 = 0Minimum spindle speed [RPM]
$32 = 0Laser-mode enable [boolean]
$100 = 200.000X-axis travel resolution [step/mm]
$101 = 200.000Y-axis travel resolution [step/mm]
$102 = 200.000Z-axis travel resolution [step/mm]
$110 = 4000.000X-axis maximum rate [mm/min]
$111 = 4000.000Y-axis maximum rate [mm/min]
$112 = 3000.000Z-axis maximum rate [mm/min]
$120 = 750.000X-axis acceleration [mm/sec^2]
$121 = 750.000Y-axis acceleration [mm/sec^2]
$122 = 500.000Z-axis acceleration [mm/sec^2]
$130 = 812.000X-axis maximum travel [millimeters]
$131 = 812.000Y-axis maximum travel [millimeters]
$132 = 105.000Z-axis maximum travel [millimeters]

To change a setting, simply send the command that corresponds to what setting you want to change. For example, if I want to set my maximum feed rate in the Z-axis to 1500mm/min, then I would send the command “$112=1500”.

If you’re using UGS, you can also directly import the LongMills firmware settings using this downloadable file: LongMill UGS Firmware Config

For advanced users, or users that want to add additional functionality such as with end stops and lasers, you may make changes to these settings.