@parrs
This might make it a bit easier to read, just imbedded your code
config.g
; Configuration file for Duet 3 (firmware version 3)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v3.1.4 on Thu Sep 10 2020 12:31:28 GMT-0600 (Mountain Daylight Time)
; General preferences
G90 ; send absolute coordinates...
M83 ; ...but relative extruder moves
M550 P"Duet3" ; sets printer name
M453 ; sets CNC mode
; Drives
M569 P0.0 S0 ; physical drive 0.0 goes reverse
M569 P0.1 S1 ; physical drive 0.1 goes forwards
M569 P0.2 S1 ; physical drive 0.2 goes forwards
M569 P0.3 S0 ; physical drive 0.3 goes reverse
M569 P0.4 S0 ; physical drive 0.4 goes reverse
M569 P0.5 S1 ; physical drive 0.5 goes forwards
M569 P1.0 S1 ; physical drive 1.0 goes forwards
M569 P1.1 S1 ; physical drive 1.1 goes forwards
M569 P1.2 S1 ; physical drive 1.2 goes forwards
M569 P2.1 S1 ; physical drive 2.1 goes forwards
M569 P2.2 S0 ; physical drive 2.2 goes forwards
M584 X0.0 Y0.1:0.2 Z0.4 U0.3 V0.5 B2.2 E1.0 ; set drive mapping
M350 X32 Y32 Z64 U32 V64 B32 E16 I1 ; configure microstepping with interpolation
M92 X800.00 Y795.9565 Z1592.718 U800.0 V1592.718 B70 E1000 ; set steps per mm
M566 X800.00 Y800.00 Z800.00 U800.00 V800.00 B1000.00 E8000.00 ; set maximum instantaneous speed changes (mm/min)
M203 X3000.00 Y3000.00 Z3000.00 U3000 V3000 B30000.00 E10000.00 ; set maximum speeds (mm/min)
M201 X200.00 Y200.00 Z200.00 U200.00 V200.00 B500.0 E250.00 ; set accelerations (mm/s^2)
M906 X2000 Y2000 Z2000 U2000 V2000 B2000 E1800 I100 ; set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout
; Axis Limits
M208 X85 Y0 Z0 U0 V0 B-500000 S1 ; set axis minima
M208 X677 Y810 Z187.6 U615 V200 B500000 S0 ; set axis maxima. z default with 5/8 spoil board 190.
; Endstops
M574 X2 S1 P"!io0.in" ; configure active-high endstop for low end on X via pin io0.in
M574 Y1 S1 P"!io1.in+!io2.in" ; configure active-high endstop for low end on Y via pin io1.in
M574 Z2 S1 P"!io4.in" ; configure active-high endstop for high end on Z via pin io2.in
M574 U1 S1 P"!io3.in" ; configure active-high endstop for high end on U via pin io2.in
M574 V2 S1 P"!io5.in" ; configure active-high endstop for high end on V via pin io2.in
; Z-Probe
M558 P0 H5 F120 T6000 ; disable Z probe but set dive height, probe speed and travel speed
M557 X15:215 Y15:195 S20 ; define mesh grid
; Heaters
//M308 S0 P"temp0" Y"pt1000" R2200 ; configure sensor 0 as PT1000 on pin temp0
//M950 H0 C"out0" T0 ; create bed heater output on out0 and map it to sensor 0
//M307 H0 B0 S1.00 ; disable bang-bang mode for the bed heater and set PWM limit
//M140 H0 ; map heated bed to heater 0
//M143 H0 S120 ; set temperature limit for heater 0 to 120C
//M308 S1 P"1.temp2" Y"thermistor" T100000 B4138 ; configure sensor 1 as thermistor on pin 1.temp2
//M950 H1 C"!out1" T1 ; create nozzle heater output on !out1 and map it to sensor 1
//M307 H1 B0 S1.00 ; disable bang-bang mode for heater and set PWM limit
; Fans
//M950 F0 C"!out4" Q500 ; create fan 0 on pin !out4 and set its frequency
//M106 P0 S0 H-1 ; set fan 0 value. Thermostatic control is turned off
//M950 F1 C"!out3" Q500 ; create fan 1 on pin !out3 and set its frequency
//M106 P1 S1 H-1 ; set fan 1 value. Thermostatic control is turned off
; Tools
M563 P0 S"Extruder" D0 F0 ; define tool 0
G10 P0 X0 Y0 Z0 ; set tool 0 axis offsets
G10 P0 R0 S0 ; set initial tool 0 active and standby temperatures to 0C
M563 P1 S"Mill" F0 ;X3 ; define tool 1 (U axis mapped to X axis)
G10 P1 X0 Y0 Z0 ; set tool 1 axis offsets
G10 P1 R0 S0 ; set initial tool 1 active and standby temperatures to 0C
;Spindle
M453 S0 C"out9" R12000 T1 F100 ; creates spindle S0 sets PWM out to pin 9
;Original code above
;//M563 P1 S"Mill" D1 F0 ; define tool 1
;//G10 P1 X0 Y0 Z0 ; set tool 1 axis offsets
;//G10 P1 R0 S0
; Custom settings are not defined
; Miscellaneous
M501 ; load saved parameters from non-volatile memory
homeall.g
; homeall.g
; called to home all axes
;
; generated by RepRapFirmware Configuration Tool v3.1.4 on Thu Sep 10 2020 12:31:28 GMT-0600 (Mountain Daylight Time)
T0
M116
G91 ; relative positioning
G1 H1 Z200 F1200 ; move Z up stopping at the endstop
G1 H1 V200 F1200 ; move V up stopping at the endstop
G1 H2 Z-10 V-10 F6000 ; go back a few mm
G92 Z187.6 V195 ; set Z and V position to axis minimum (you may want to adjust this)
G1 H2 Z5 V5 F6000 ; lift Z and V relative to current position
G1 H1 X+705 Y-816 U-705 F1800 ; move quickly to X and Y axis endstops and stop there (first pass)
G1 H2 X-5 Y5 U5 F6000 ; go back a few mm
G1 H1 X+705 Y-816 U-705 F360 ; move slowly to X and Y axis endstops once more (second pass)
G90 ; absolute positioning
G92 B0 ; Set position - B axis (rotary) to 0
;T0
; Uncomment the following lines to lift Z after probing
;G91 ; relative positioning
;G1 Z5 F100 ; lift Z relative to current position
;G90 ; absolute positioning
tfree0.g
; Operations to be done before switching from T0 to T1 (EXTRUDER TO MILL)
;TOOL ZERO MOVEMENTS (EXTRUDER)
G90 ;ABSOLUTE COORDINATES
G1 Z185 ;LIFT Z TO PARK LOCATION
G1 X675 ;MOVE X TO PARK LOCATION (FAR RIGHT OF MACHINE)
tfree1.g
;Operations to be done before switching from T1 to T0
;DO THESE NEED TO BE X AND Z VALUES OR U AND V??????????????????
G90 ;ABSOLUTE MOVEMENTS
G1 Z185 ;LIFT T1
G1 X0 ;MOVE T1 TO PARK POSITION (LEFT SIDE OF MACHINE)
;THESE VALUES NEED TO MATCH TPRE1.G PARK VALUES AS THE MACHINE OVERWRITES TOOL LOCATION WHEN SWITCHING. NEEDS TO KNOW WHERE IT IS
tpre0.g
;Operations/configurations to be set when T0 selected - NOTE THIS OVERRIDES THE CONFIG.G PARAMETERS AFTER SWITCHING TOOLS
;NOTE: ENDSTOPS HAVE NOT BEEN RECONFIGURED FROM CONFIG.G - MAY NEED TO BE
;M451 ;SET TO FFF PRINT MODE
M584 X0.0 Z0.4 U0.3 V0.5 ;SET DRIVE MAPPING (EXT NOW CONTROLLED BY X AND Z COMMANDS) - REMAP T1 TO U&V
M350 X32 Z64 ;SET MICROSTEPPING
M92 X800 Z1592.718 ;SET STEPS/MM (VALUE NEEDED FOR MILL Z AXIS - REMEMBER MILL AND EXTRUDER MAY BE DIFFERENT) **UPDATE**
M566 X800 Z800 ;SET INSTANTANEOUS SPEED CHANGES (MM/MIN)
M203 X3000 Z3000 ;SET MAXIMUM SPEEDS (MM/MIN)
M201 X200 Z200 ;SET ACCELERATION (MM/S^2)
M208 X85 S1 ;SETS AXIS MINIMUM (MAKE IT SO IT WONT COLLIDE WITH MILL) S1 DENOTES MIN WHERE S0 OR BLANK DENOTES MAX
M208 X677
G92 X675 Z185 ;SET POSITION - SET TO MATCH PARK VALUES (TFREE0.G) SO SOFTWARE KNOWS WHERE TOOL IS AFTER SWITCHING
tpre1.g
;Operations/configurations to be set when T1 selected - NOTE THIS OVERRIDES THE CONFIG.G PARAMETERS AFTER SWITCHING TOOLS
;NOTE: ENDSTOPS HAVE NOT BEEN RECONFIGURED FROM CONFIG.G - MAY NEED TO BE
M453 ;SET TO CNC MODE
M584 X0.3 Z0.5 ;SET DRIVE MAPPING (MILL NOW CONTROLLED BY X AND Z COMMANDS)
M350 X32 Z64 ;SET MICROSTEPPING
M92 X800 Z1592.718 ;SET STEPS/MM (VALUE NEEDED FOR MILL Z AXIS - REMEMBER MILL AND EXTRUDER MAY BE DIFFERENT)
M566 X800 Z800 ;SET INSTANTANEOUS SPEED CHANGES (MM/MIN)
M203 X3000 Z3000 ;SET MAXIMUM SPEEDS (MM/MIN)
M201 X200 Z200 ;SET ACCELERATION (MM/S^2)
M208 X0 S1 ;SETS AXIS MINIMUM (S1 DENOTES MINIMUM WHERE S0 OR BLANK DENOTES MAX)
M208 X615 ;SETS AXIS MAXIMUM (ENSURE CLEARANCE IS MAINTAINED IN RESPECT TO T0 IN PARK LOCATION)
G92 X0 Z185 ;SET POSITION - SET TO MATCH PARK VALUES (TFREE1.G) SO SOFTWARE KNOWS WHERE TOOL IS AFTER SWITCHING