Unlimited Endstop Usage

Notes

Prerequisites

• Must meet all the following conditions:

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

Motherboard Compatibility Check

Classification of Fly Motherboards:

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 feature unavailable

Identification method:

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

Type A Motherboard No DIAG jumper, direct connection by default to the endstop port

Type B Motherboard Requires DIAG jumper

Driver Compatibility Check

Tip

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

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

Key Identification Points:

1. Dual-pin drivers must consult the corresponding manual to confirm function pins
2. Some drivers support DIAG function, but if the corresponding header is not soldered, it cannot be used

Configuration Instructions

• Need to modify the corresponding driver model and axis
• Some machines using unlimited endstop homing may fail homing during retraction; set homing_retract_dist: to 0

Reference Configurations

• In tmc2209_stepper_x, TMC2209 needs to be changed to the corresponding driver model
• In stepper_x, x indicates this is the x-axis; if it is the y-axis, change to stepper_y

TMC2209 Reference Configuration

• The pins in the configuration below are for reference only; adjust according to your actual setup
• The diag_pin: configuration must include ^, or homing will fail
• The value in driver_SGTHRS: must 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; adjust according to your actual setup
• 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: must 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; adjust according to your actual setup
• 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: must 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; adjust according to your actual setup
• 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: must 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 the sensitivity

  • Use the following command for TMC2209, modify the axis you are testing

    SET_TMC_FIELD STEPPER=stepper_x FIELD=SGTHRS VALUE=255

  • Use the following command for TMC5160, TMC2240, and TMC2130, 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 either doesn't move at all or stops moving quickly
  • If there is no movement, immediately issue the following command

    M112

  • Check the wiring or configuration of the corresponding DIAG PIN pin; any error must be corrected before continuing

• Step 3

  • Next, gradually decrease the VALUE sensitivity setting and rerun the SET_TMC_FIELD and G28 X0 commands
  • Find the highest sensitivity that allows the carriage to move all the way to the end and stop reliably
  • For TMC2209 drivers, decrease SGTHRS; for other drivers, increase sgt

• Step 4

  • Once a suitable value is found, remember it after homing as soon as it stops upon 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 the axis may not be suitable for sensorless homing
  • Open printer.cfg and update the corresponding sensitivity configuration