diff --git a/libraries/AP_ADC/AP_ADC_ADS7844.cpp b/libraries/AP_ADC/AP_ADC_ADS7844.cpp
index af3ee6bac6..edc599decc 100644
--- a/libraries/AP_ADC/AP_ADC_ADS7844.cpp
+++ b/libraries/AP_ADC/AP_ADC_ADS7844.cpp
@@ -171,7 +171,7 @@ void AP_ADC_ADS7844::Init()
 
     _ch6_last_sample_time_micros = hal.scheduler->micros();
 
-    hal.scheduler->register_timer_process( reinterpret_cast<AP_HAL::TimedProc>(&AP_ADC_ADS7844::read), this );
+    hal.scheduler->register_timer_process(AP_HAL_MEMBERPROC(&AP_ADC_ADS7844::read));
     hal.scheduler->resume_timer_procs();
 
 }
diff --git a/libraries/AP_ADC/AP_ADC_HIL.cpp b/libraries/AP_ADC/AP_ADC_HIL.cpp
index b60ed390a1..806aea5f93 100644
--- a/libraries/AP_ADC/AP_ADC_HIL.cpp
+++ b/libraries/AP_ADC/AP_ADC_HIL.cpp
@@ -49,7 +49,7 @@ AP_ADC_HIL::AP_ADC_HIL()
 
 void AP_ADC_HIL::Init()
 {
-    hal.scheduler->register_timer_process( reinterpret_cast<AP_HAL::TimedProc>(&AP_ADC_HIL::read), this);
+    hal.scheduler->register_timer_process( AP_HAL_MEMBERPROC(&AP_ADC_HIL::read));
 }
 
 // Read one channel value