Protection on the sensor inputs to the micro

[reesesm2000]

Version Number

All

Bugfix or Enhancement

Enhancement

Description

The limit switch sensor inputs are delivered straight into the ST microcontroller without any protection or filtering.

Suggested Solution

At least add a low pass filter (RC with 1.5k resistor and 1uF capacitor) to the line from the input connector to the micro. This will provide a low pass filter with ~106Hz cutoff which is plenty for the limit switch. A TVS diode would probably also be a good addition.
This will also stop any interference from the cables of the steppers.