manual_stepper: Support registering as an additional axis

Add a new G-Code command that can register a manual_stepper as an
additional axis on standard G-Code G1 commands.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 12 insertions, 0 deletions

diff --git a/docs/G-Codes.md b/docs/G-Codes.md
index b8a0ce69..6d69dd9c 100644
--- a/docs/G-Codes.md
+++ b/docs/G-Codes.md
@@ -968,6 +968,18 @@ scheduled to run after the stepper move completes, however if a manual
 stepper move uses SYNC=0 then future G-Code movement commands may run
 in parallel with the stepper movement.
 
+`MANUAL_STEPPER STEPPER=config_name GCODE_AXIS=[A-Z]`: If the
+`GCODE_AXIS` parameter is specified then it configures the stepper
+motor as an extra axis on `G1` move commands.  For example, if one
+were to issue a `MANUAL_STEPPER ... GCODE_AXIS=R` command then one
+could issue commands like `G1 X10 Y20 R30` to move the stepper motor.
+The resulting moves will occur synchronously with the associated
+toolhead xyz movements.  If the motor is associated with a
+`GCODE_AXIS` then one may no longer issue movements using the above
+`MANUAL_STEPPER` command - one may unregister the stepper with a
+`MANUAL_STEPPER ... GCODE_AXIS=` command to resume manual control of
+the motor.
+
 ### [mcp4018]
 
 The following command is available when a