---
tag: m0914
title: TMC Bump Sensitivity
brief: Set sensorless homing sensitivity
author: thinkyhead,mbuc
contrib: saikek, shitcreek

group: trinamic
requires: SENSORLESS_HOMING
eeprom: true

codes: [ M914 ]

notes:
- Set all `*_HOME_BUMP_MM` values to 0 for best results.
- Set the default stall thresholds with `*_STALL_SENSITIVITY`.
- |
  Compatible with TMC2130 and TMC2209.

  |Sensitivity|TMC2209|Others|
  |--|--|--|
  |LOWEST|0|+63|
  |HIGHEST|255|-64|

- High sensitivity may produce false positives.
- Low sensitivity may fail to trigger.

parameters:

- tag: I
  optional: true
  since: 1.1.9
  description: Index for multiple steppers. (i.e., `I1` for X2, Y2, Z2; `I2` for Z3; `I3` for Z4).
  values:
  - unit: index
    type: int

- tag: X
  optional: true
  description: Sensitivity of the X stepper driver.
  values:
  - type: int

- tag: Y
  optional: true
  description: Sensitivity of the Y stepper driver.
  values:
  - type: int

- tag: Z
  optional: true
  description: Sensitivity of the Z stepper driver.
  values:
  - type: int

- tag: A
  optional: true
  since: 2.0.9
  requires: I_DRIVER_TYPE, AXIS4_NAME 'A'
  description: Sensitivity of the A stepper driver.
  values:
  - type: int

- tag: B
  optional: true
  since: 2.0.9
  requires: J_DRIVER_TYPE, AXIS5_NAME 'B'
  description: Sensitivity of the B stepper driver.
  values:
  - type: int

- tag: C
  optional: true
  since: 2.0.9
  requires: K_DRIVER_TYPE, AXIS6_NAME 'C'
  description: Sensitivity of the C stepper driver.
  values:
  - type: int

- tag: U
  optional: true
  since: 2.1
  requires: U_DRIVER_TYPE, AXIS7_NAME 'U'
  description: Sensitivity of the U stepper driver.
  values:
  - type: int

- tag: V
  optional: true
  since: 2.1
  requires: V_DRIVER_TYPE, AXIS8_NAME 'V'
  description: Sensitivity of the V stepper driver.
  values:
  - type: int

- tag: W
  optional: true
  since: 2.1
  requires: W_DRIVER_TYPE, AXIS9_NAME 'W'
  description: Sensitivity of the W stepper driver.
  values:
  - type: int

---

Some TMC stepper drivers can detect when they bump into something that causes them to stop moving. This feature is so sensitive that it can actually take the place of traditional endstops. Use this command to set the bump sensitivity for the X, Y, Z, ... stepper drivers.

Value Ranges:
- TMC2208: 0 .. 255
- TMC2130: -64 .. +63
