Config files: update comment/help text for USE_INTERNAL_PULLUPS.

config/printer.mendel.h

@@ -171,10 +171,14 @@
 \***************************************************************************/
 
 /** \def USE_INTERNAL_PULLUPS
-  The ATmega has internal pullup resistors on it's input pins which are
-  counterproductive with the commonly used eletronic endstops, so they should
-  be switched off. For other endstops, like mechanical ones, you may want to
-  uncomment this.
+
+  Most controller chips feature internal pullup resistors on their input pins,
+  which get used for endstops by turning on this switch. Don't turn it on when
+  using endstops which need no pull resistor, e.g. optical endstops, because
+  pull resistors are counterproductive there.
+
+  One can't use USE_INTERNAL_PULLUPS and USE_INTERNAL_PULLDOWNS at the same
+  time, of course.
 */
 //#define USE_INTERNAL_PULLUPS
 

config/printer.mendel90.h

@@ -171,10 +171,14 @@
 \***************************************************************************/
 
 /** \def USE_INTERNAL_PULLUPS
-  The ATmega has internal pullup resistors on it's input pins which are
-  counterproductive with the commonly used eletronic endstops, so they should
-  be switched off. For other endstops, like mechanical ones, you may want to
-  uncomment this.
+
+  Most controller chips feature internal pullup resistors on their input pins,
+  which get used for endstops by turning on this switch. Don't turn it on when
+  using endstops which need no pull resistor, e.g. optical endstops, because
+  pull resistors are counterproductive there.
+
+  One can't use USE_INTERNAL_PULLUPS and USE_INTERNAL_PULLDOWNS at the same
+  time, of course.
 */
 //#define USE_INTERNAL_PULLUPS
 

config/printer.tronxy.h

@@ -171,10 +171,14 @@
 \***************************************************************************/
 
 /** \def USE_INTERNAL_PULLUPS
-  The ATmega has internal pullup resistors on it's input pins which are
-  counterproductive with the commonly used eletronic endstops, so they should
-  be switched off. For other endstops, like mechanical ones, you may want to
-  uncomment this.
+
+  Most controller chips feature internal pullup resistors on their input pins,
+  which get used for endstops by turning on this switch. Don't turn it on when
+  using endstops which need no pull resistor, e.g. optical endstops, because
+  pull resistors are counterproductive there.
+
+  One can't use USE_INTERNAL_PULLUPS and USE_INTERNAL_PULLDOWNS at the same
+  time, of course.
 */
 //#define USE_INTERNAL_PULLUPS
 

config/printer.wolfstrap.h

@@ -171,10 +171,14 @@
 \***************************************************************************/
 
 /** \def USE_INTERNAL_PULLUPS
-  The ATmega has internal pullup resistors on it's input pins which are
-  counterproductive with the commonly used eletronic endstops, so they should
-  be switched off. For other endstops, like mechanical ones, you may want to
-  uncomment this.
+
+  Most controller chips feature internal pullup resistors on their input pins,
+  which get used for endstops by turning on this switch. Don't turn it on when
+  using endstops which need no pull resistor, e.g. optical endstops, because
+  pull resistors are counterproductive there.
+
+  One can't use USE_INTERNAL_PULLUPS and USE_INTERNAL_PULLDOWNS at the same
+  time, of course.
 */
 //#define USE_INTERNAL_PULLUPS
 

configtool/printer.generic.h

@@ -171,10 +171,14 @@
 \***************************************************************************/
 
 /** \def USE_INTERNAL_PULLUPS
-  The ATmega has internal pullup resistors on it's input pins which are
-  counterproductive with the commonly used eletronic endstops, so they should
-  be switched off. For other endstops, like mechanical ones, you may want to
-  uncomment this.
+
+  Most controller chips feature internal pullup resistors on their input pins,
+  which get used for endstops by turning on this switch. Don't turn it on when
+  using endstops which need no pull resistor, e.g. optical endstops, because
+  pull resistors are counterproductive there.
+
+  One can't use USE_INTERNAL_PULLUPS and USE_INTERNAL_PULLDOWNS at the same
+  time, of course.
 */
 #define USE_INTERNAL_PULLUPS
 

testcases/config.h.Profiling

@@ -269,15 +269,15 @@
 *                                                                           *
 \***************************************************************************/
 
-/*
-	Machine Pin Definitions
-	- make sure to avoid duplicate usage of a pin
-	- comment out pins not in use, as this drops the corresponding code and makes operations faster
-*/
-
 /** \def USE_INTERNAL_PULLUPS
-	internal pullup resistors
-		the ATmega has internal pullup resistors on it's input pins which are counterproductive with the commonly used eletronic endstops, so they should be switched off. For other endstops, like mechanical ones, you may want to uncomment this.
+
+  Most controller chips feature internal pullup resistors on their input pins,
+  which get used for endstops by turning on this switch. Don't turn it on when
+  using endstops which need no pull resistor, e.g. optical endstops, because
+  pull resistors are counterproductive there.
+
+  One can't use USE_INTERNAL_PULLUPS and USE_INTERNAL_PULLDOWNS at the same
+  time, of course.
 */
 //#define USE_INTERNAL_PULLUPS