RUMBA32 V1.1 User Manual – Rev A
Page 9
6
E
NDSTOP
C
ONNECTORS
RUMBA32 has six endstop inputs, designated X-MIN, X-MAX, Y-MIN, Y-MAX, Z-MIN and Z-MAX.
Most bed sensors / z-probes may also be connected through one of these connectors. It is fairly
common to use the Z-MIN connector for this (specific details will vary by sensor type and firmware
configuration).
Each endstop connector has a power pin, ground pin, and signal pin.
The power pins are supplied by the 3.3V rail by default. They can be set to supply 5V by modifying the
board jumpers (see Configuration Jumpers).
Figure 4: Endstop Connectors
Each signal pin is pulled-up to 3.3V (or 5V) by a 4.7K resistor. Additionally, each endstop signal passes
through an RC filter, consisting of a 10K resistor and a 2.2nF capacitor. As this 10K resistor limits the
current that the microcontroller will sink in the event of an overvoltage, the endstop signal pins can
be safely connected to 12/24V without damaging the board. However, it is not recommended to
operate the board in this condition.
Note:
It is recommended to disable endstop pull-up resistors in your firmware. The hardware pull-up
resistors accomplish this, and the internal pull-ups enabled by firmware will form a divider with the
series resistor and may prevent correct reading under some circumstances.
Note:
The endstop signals can also be controlled by attached stepper drivers if they feature a
diagnostic output pin (such as TMC drivers with StallGuard detection). If a stepper driver with this pin
is connected, it may override the connected endstop and prevent correct detection. Refer to
Diagnostic Input (StallGuard) for more information.
