SAME5x ADCs no longer use DMA

src/AnalogIn.h

@@ -24,11 +24,14 @@ namespace AnalogIn
 #ifdef RTOS
 	// Initialise the analog input subsystem. Call this just once.
 	// For the SAME5x we need 4 DMA channels. For the SAMC21 we need 1 DMA channel, or 2 if supporting the SDADC.
-	void Init(DmaChannel dmaChan,
+	void Init(
 #if SAME5x
-		DmaPriority txPriority,
+				NvicPriority interruptPriority
+#else
+				DmaChannel dmaChan,
+				DmaPriority rxPriority
 #endif
-		DmaPriority rxPriority) noexcept;
+			) noexcept;
 
 	// Shut down the analog system. making it safe to terminate the AnalogIn task
 	void Exit() noexcept;

src/Cache.h

@@ -45,6 +45,7 @@ inline void Cache::Invalidate(const volatile void *start, size_t length) noexcep
 
 # if SAME5x
 // The SAME5x version of this cache controller allows us to disable data caching
+// Caching instructions only increases the time taken by the ADC ISR from 700ns to 750ns, so we don't do it
 #  define	CACHE_INSTRUCTIONS_ONLY		(0)
 # endif