Unlimited Endstop Usage

Precautions

Required Conditions

• Must meet all the following:

1. The motherboard supports the DIAG function
2. The driver supports DIAG signal output
3. No device should be connected to the corresponding endstop interface!

Motherboard Compatibility Check

Fly motherboard support classification:

Type	Support Status	Representative Models	Operation Requirements
A	Direct connection by default	Super/Gemini/CDY/E3 Series	✅ Direct use of endstop interface
B	Requires jumper to enable	D/C/Pro-X10/Micro Series	⚡ Must install DIAG jumper cap
C	Not supported at all	Fly-F407ZG	❌ Unlimited endstop function unavailable

Identification method:

1. Check motherboard markings: Look for a jumper labeled DIAG
2. Refer to the schematic: Confirm DIAG signal connection of the drive interface
3. On most motherboards, unlimited endstop for Drive0 corresponds to io0, Drive1 to io1, and so on

Type A Motherboard No DIAG jumper, directly connected to the corresponding endstop port by default

Type B Motherboard Requires DIAG jumper

Driver Compatibility Check

Note

• TMC5160, TMC2240, and TMC2130 have two DIAG pins
• You need to check the product documentation or contact customer support for confirmation

Driver Model	Compatibility	DIAG Pins	Configuration Requirements	Sensitivity Range
TMC2209	✅ Supported	Single Pin	Direct use	0-255 # 255 is the most sensitive, 0 is the least sensitive
TMC5160	✅ Supported	Dual Pins	Need to select diag pin	-64-255 # -64 is the most sensitive, 63 is the least sensitive
TMC2240	✅ Supported	Dual Pins	Need to select diag pin	-64-255 # -64 is the most sensitive, 63 is the least sensitive
TMC2130	✅ Supported	Dual Pins	Need to select diag pin	-64-255 # -64 is the most sensitive, 63 is the least sensitive
TMC2208	❌ Not Supported	-	Unlimited endstop function unavailable	Unlimited endstop function unavailable
TMC2660	❌ Not Supported	-	Unlimited endstop function unavailable	Unlimited endstop function unavailable
LV8729	❌ Not Supported	-	Unlimited endstop function unavailable	Unlimited endstop function unavailable

Key identification points:

1. Dual-pin drivers must refer to the manual to confirm the function pin
2. Some drivers support the DIAG function but may not be usable if the corresponding pin header is not soldered

Configuration Instructions

• Modify the corresponding driver model and axis
• Some machines may fail homing due to retraction when using unlimited endstop; set homing_retract_dist: to 0

Reference Configurations

• In tmc2209_stepper_x, TMC2209 should be changed to the actual driver model
• In stepper_x, x represents the X-axis; if it's the Y-axis, change to stepper_y

TMC2209 Reference Configuration

• The pins in the configuration below are for reference only; actual wiring may vary
• The diag_pin: configuration must include ^, or homing will fail
• The value in driver_SGTHRS: needs to be tested and set; 255 is the most sensitive, 0 is the least sensitive

  [stepper_x]
  endstop_pin: tmc2209_stepper_x:virtual_endstop
  position_endstop: 0
  
  
  [tmc2209 stepper_x]
  diag_pin: ^PD9
  driver_SGTHRS: 100

TMC5160 Reference Configuration

• The pins in the configuration below are for reference only; actual wiring may vary
• Refer to the product manual to determine whether to use diag0_pin: or diag1_pin:
• The diag1_pin: configuration must include ^!, or homing will fail
• The value in driver_SGT: needs to be tested and set; -64 is the most sensitive, 63 is the least sensitive

  [stepper_y]
  endstop_pin: tmc5160_stepper_y:virtual_endstop
  position_endstop: 0
  
  
  [tmc5160 stepper_y]
  diag1_pin: ^!PD9
  driver_SGT: 1

TMC2130 Reference Configuration

• The pins in the configuration below are for reference only; actual wiring may vary
• Refer to the product manual to determine whether to use diag0_pin: or diag1_pin:
• The diag1_pin: configuration must include ^!, or homing will fail
• The value in driver_SGT: needs to be tested and set; -64 is the most sensitive, 63 is the least sensitive

  [stepper_y]
  endstop_pin: tmc2130_stepper_y:virtual_endstop
  position_endstop: 0
  
  
  [tmc2130 stepper_y]
  diag1_pin: ^!PD9
  driver_SGT: 1

TMC2240 Reference Configuration

• The pins in the configuration below are for reference only; actual wiring may vary
• Refer to the product manual to determine whether to use diag0_pin: or diag1_pin:
• The diag1_pin: configuration must include ^!, or homing will fail
• The value in driver_SGT: needs to be tested and set; -64 is the most sensitive, 63 is the least sensitive

  [stepper_x]
  endstop_pin: tmc2240_stepper_x:virtual_endstop
  position_endstop: 0
  
  
  [tmc2240 stepper_x]
  diag1_pin: ^!PD9
  driver_SGT: 1

Testing Sensitivity

• Step 1

  • Enter the following command in the web console

  • Move the print head slowly to the center of the machine. Use the SET_TMC_FIELD command to set sensitivity

  • For TMC2209, use the command below and modify the axis you are testing

    SET_TMC_FIELD STEPPER=stepper_x FIELD=SGTHRS VALUE=255

  • For TMC5160, TMC2240, and TMC2130, use the command below and modify the axis you are testing

    SET_TMC_FIELD STEPPER=stepper_x FIELD=sgt VALUE=-64

• Step 2

  • Enter the following command in the web console

    G28 X

  • Confirm that the X-axis does not move at all or stops moving quickly
  • If no movement notification is received, immediately issue the following command

    M112

  • Check for wiring or configuration errors on the corresponding DIAG PIN pin; these must be corrected before proceeding

• Step 3

  • Next, gradually reduce the sensitivity value set by VALUE and run the SET_TMC_FIELD and G28 X0 commands again
  • Find the highest sensitivity that allows the carriage to move successfully to the end point and stop

• Step 4

  • Once the appropriate value is found, remember it after homing when it stops on the slightest touch
  • If there is a knocking or clicking sound at maximum sensitivity, the homing speed may be too low, the driver current may be too low, or this axis may not be suitable for sensorless homing
  • Open printer.cfg and update the corresponding sensitivity configuration