diff --git a/config/printer.mendel.h b/config/printer.mendel.h
index a372f39..e134238 100644
--- a/config/printer.mendel.h
+++ b/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
 
diff --git a/config/printer.mendel90.h b/config/printer.mendel90.h
index 6c4aee6..3e3fdfe 100644
--- a/config/printer.mendel90.h
+++ b/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
 
diff --git a/config/printer.tronxy.h b/config/printer.tronxy.h
index 761d0f9..c638ed0 100644
--- a/config/printer.tronxy.h
+++ b/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
 
diff --git a/config/printer.wolfstrap.h b/config/printer.wolfstrap.h
index 6069fa1..6d22323 100644
--- a/config/printer.wolfstrap.h
+++ b/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
 
diff --git a/configtool/printer.generic.h b/configtool/printer.generic.h
index 6cfbc6a..e8625e6 100644
--- a/configtool/printer.generic.h
+++ b/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
 
diff --git a/testcases/config.h.Profiling b/testcases/config.h.Profiling
index f371528..558ae70 100644
--- a/testcases/config.h.Profiling
+++ b/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