diff --git a/CommandStation-EX.ino b/CommandStation-EX.ino
index d2627ea..219e245 100644
--- a/CommandStation-EX.ino
+++ b/CommandStation-EX.ino
@@ -101,7 +101,6 @@ void setup()
 
   // Invoke any DCC++EX commands in the form "SETUP("xxxx");"" found in optional file mySetup.h.
   //  This can be used to create turnouts, outputs, sensors etc. through the normal text commands.
-// PMA - how to handle __has_include??
   #if __has_include ( "mySetup.h")
     #define SETUP(cmd) DCCEXParser::parse(F(cmd))
     #include "mySetup.h"
diff --git a/DCCTimerSAMD.cpp b/DCCTimerSAMD.cpp
index 74ec18b..a3f9c00 100644
--- a/DCCTimerSAMD.cpp
+++ b/DCCTimerSAMD.cpp
@@ -37,8 +37,33 @@ INTERRUPT_CALLBACK interruptHandler=0;
 void DCCTimer::begin(INTERRUPT_CALLBACK callback) {
   interruptHandler=callback;
 
+  // PMA - SAMC used on Firebox has 2 ADCs, so choose which to set up based on pin being used
+  // TODO: this code will need to be fixed - ADCpin is not in scope... as this is stolen from 
+  // the abandoned rf24 branch
+  #if defined(ARDUINO_ARCH_SAMC)
+  Adc* ADC;
+  if ( (g_APinDescription[ADCpin].ulPeripheralAttribute & PER_ATTR_ADC_MASK) == PER_ATTR_ADC_STD ) {
+      ADC = ADC0;
+  } else {
+    ADC = ADC1;
+  }
+  #endif
 
+  // PMA - Set up ADC to do faster reads... default for Arduino Zero platform configs is 436uS,
+  // and we need sub-100uS. This code sets it to a read speed of around 21uS, and enables 12-bit
+  ADC->CTRLA.bit.ENABLE = 0;              // disable ADC
+  while( ADC->STATUS.bit.SYNCBUSY == 1 ); // wait for synchronization
 
+  ADC->CTRLB.reg &= 0b1111100011111111;          // mask PRESCALER bits
+  ADC->CTRLB.reg |= ADC_CTRLB_PRESCALER_DIV64 |  // divide Clock by 64
+                    ADC_CTRLB_RESSEL_12BIT;      // Result on 12 bits
+
+  ADC->AVGCTRL.reg = ADC_AVGCTRL_SAMPLENUM_1 |   // take 1 sample at a time
+                     ADC_AVGCTRL_ADJRES(0x00ul); // adjusting result by 0
+  ADC->SAMPCTRL.reg = 0x00;                      // sampling Time Length = 0
+
+  ADC->CTRLA.bit.ENABLE = 1;                     // enable ADC
+  while(ADC->STATUS.bit.SYNCBUSY == 1);          // wait for synchronization
 
   }
 
diff --git a/MotorDrivers.h b/MotorDrivers.h
index b2b798d..accddf1 100644
--- a/MotorDrivers.h
+++ b/MotorDrivers.h
@@ -46,9 +46,17 @@
 // (HIGH == release brake)
 //
 // Arduino standard Motor Shield
+#if defined(ARDUINO_ARCH_SAMD)
+// PMA - senseFactor for 3.3v systems is 1.95 as calculated when using 10-bit A/D samples,
+// and for 12-bit samples it's more like 0.488, but we probably need to tweak both these
+#define STANDARD_MOTOR_SHIELD F("STANDARD_MOTOR_SHIELD"),                                                 \
+                              new MotorDriver(3, 12, UNUSED_PIN, 9, A0, 0.488, 2000, UNUSED_PIN), \
+                              new MotorDriver(11, 13, UNUSED_PIN, 8, A1, 0.488, 2000, UNUSED_PIN)
+#else
 #define STANDARD_MOTOR_SHIELD F("STANDARD_MOTOR_SHIELD"),                                                 \
                               new MotorDriver(3, 12, UNUSED_PIN, 9, A0, 2.99, 2000, UNUSED_PIN), \
                               new MotorDriver(11, 13, UNUSED_PIN, 8, A1, 2.99, 2000, UNUSED_PIN)
+#endif
 
 // Pololu Motor Shield
 #define POLOLU_MOTOR_SHIELD F("POLOLU_MOTOR_SHIELD"),                                                 \