RUMBA32 V1.1 User Manual – Rev A
Page 17
13.2
D
IAGNOSTIC
I
NPUT
(S
TALL
G
UARD
)
RUMBA32 provides an easy way to connect stepper drivers to the endstop pins. This can be useful
when using TMC stepper drivers with StallGuard detection, in order to implement sensorless homing.
Each stepper driver socket features a pin that can connect the stepper driver to an associated endstop
input. This requires the stepper driver to have the DIAG pin installed. An example of such a driver is
shown in Figure 15.
Figure 15: TMC2209 with DIAG pin (red pin, third from edge) installed
The drivers and endstops are matched as follows:
Stepper Driver
Endstop Signal
Microcontroller Pin
X
X-MIN
PB12
Y
Y-MIN
PB15
Z
Z-MIN
PD9
E0
X-MAX
PB13
E1
Y-MAX
PD8
E2
Z-MAX
PD10
For TMC stepper drivers that have this DIAG pin, sensorless homing can be enabled in firmware
without requiring any additional wiring.
13.2.1
Conflict with Endstop Signal
When connecting stepper drivers with the DIAG pin installed, the stepper driver’s DIAG signal may
override any connected endstop and prevent it from being detected by the firmware.
If you are using a stepper driver with the DIAG pin, but do not require StallGuard and intend to use
the associated endstop, it is recommended to ensure that the DIAG signal is not connected. This can
be achieved the following ways:
•
Remove (desolder or trim away) the DIAG pin from the stepper driver
•
Remove (desolder or trim away) the DIAG connector in the driver socket on RUMBA32
•
Bend the DIAG connector on RUMBA32 so that the driver DIAG pin does not enter it
•
Desolder the resistor on RUMBA32 immediately below the DIAG connector