Merge commit '71bb657e3a7d80edc096094564f5d279e8a1fb69'

* commit '71bb657e3a7d80edc096094564f5d279e8a1fb69':
  Esp32 iram attr (#26)

The merge adds extra STM32 handling

Als manually resolved the conflict around the type for lastMicros, to now be:

	    static unsigned int  lastMicros = 0;

Howefully this does the right thing on each platform

NmraDcc.h

@@ -53,6 +53,8 @@
 
 #define MAX_DCC_MESSAGE_LEN 6    // including XOR-Byte
 
+//#define ALLOW_NESTED_IRQ      // uncomment to enable nested IRQ's ( only for AVR! )
+
 typedef struct
 {
 	uint8_t	Size ;
@@ -105,6 +107,9 @@ typedef struct
 #elif defined( __STM32F1__)
 	#define MAXCV	(EEPROM_PAGE_SIZE/4 - 1)	// number of storage places (CV address could be larger
 											// because STM32 uses virtual adresses)
+    #undef ALLOW_NESTED_IRQ                 // This is done with NVIC on STM32
+    #define PRIO_DCC_IRQ    9
+    #define PRIO_SYSTIC     8               // MUST be higher priority than DCC Irq
 #else
 	#define MAXCV    E2END     					// the upper limit of the CV value currently defined to max memory.
 #endif