diff --git a/Marlin/src/HAL/HAL_DUE/HAL_Due.cpp b/Marlin/src/HAL/HAL_DUE/HAL_Due.cpp
index 078857ec0..b3a5d469a 100644
--- a/Marlin/src/HAL/HAL_DUE/HAL_Due.cpp
+++ b/Marlin/src/HAL/HAL_DUE/HAL_Due.cpp
@@ -112,7 +112,7 @@ int freeMemory() {
 // ADC
 // --------------------------------------------------------------------------
 
-void HAL_adc_start_conversion(uint8_t adc_pin) {
+void HAL_adc_start_conversion(const uint8_t adc_pin) {
   HAL_adc_result = analogRead(adc_pin);
 }
 
diff --git a/Marlin/src/HAL/HAL_DUE/HAL_Due.h b/Marlin/src/HAL/HAL_DUE/HAL_Due.h
index 2b8cca809..f71b8ff49 100644
--- a/Marlin/src/HAL/HAL_DUE/HAL_Due.h
+++ b/Marlin/src/HAL/HAL_DUE/HAL_Due.h
@@ -150,7 +150,7 @@ inline void HAL_adc_init(void) {}//todo
 #define HAL_READ_ADC        HAL_adc_result
 
 
-void HAL_adc_start_conversion (uint8_t adc_pin);
+void HAL_adc_start_conversion(const uint8_t adc_pin);
 
 uint16_t HAL_adc_get_result(void);
 
diff --git a/Marlin/src/HAL/HAL_LPC1768/HAL.cpp b/Marlin/src/HAL/HAL_LPC1768/HAL.cpp
index 181180fe4..5f5c3f047 100644
--- a/Marlin/src/HAL/HAL_LPC1768/HAL.cpp
+++ b/Marlin/src/HAL/HAL_LPC1768/HAL.cpp
@@ -113,7 +113,7 @@ void HAL_adc_enable_channel(int pin) {
   };
 }
 
-void HAL_adc_start_conversion(uint8_t adc_pin) {
+void HAL_adc_start_conversion(const uint8_t adc_pin) {
   if (adc_pin >= (NUM_ANALOG_INPUTS) || adc_pin_map[adc_pin].port == 0xFF) {
     usb_serial.printf("HAL: HAL_adc_start_conversion: no pinmap for %d\n", adc_pin);
     return;
diff --git a/Marlin/src/HAL/HAL_LPC1768/HAL.h b/Marlin/src/HAL/HAL_LPC1768/HAL.h
index 96b4478d5..e1b52a681 100644
--- a/Marlin/src/HAL/HAL_LPC1768/HAL.h
+++ b/Marlin/src/HAL/HAL_LPC1768/HAL.h
@@ -91,7 +91,7 @@ uint8_t spiRec(uint32_t chan);
 
 void HAL_adc_init(void);
 void HAL_adc_enable_channel(int pin);
-void HAL_adc_start_conversion (uint8_t adc_pin);
+void HAL_adc_start_conversion(const uint8_t adc_pin);
 uint16_t HAL_adc_get_result(void);
 
 #endif // _HAL_LPC1768_H
diff --git a/Marlin/src/HAL/HAL_TEENSY35_36/HAL_Teensy.h b/Marlin/src/HAL/HAL_TEENSY35_36/HAL_Teensy.h
index fc24b5a92..e4c020847 100644
--- a/Marlin/src/HAL/HAL_TEENSY35_36/HAL_Teensy.h
+++ b/Marlin/src/HAL/HAL_TEENSY35_36/HAL_Teensy.h
@@ -122,7 +122,7 @@ void HAL_adc_init();
 
 #define HAL_ANALOG_SELECT(pin) NOOP;
 
-void HAL_adc_start_conversion(uint8_t adc_pin);
+void HAL_adc_start_conversion(const uint8_t adc_pin);
 
 uint16_t HAL_adc_get_result(void);