tweak enum

save flash

MFRC522.h

@@ -272,8 +272,8 @@ public:
 	};
 	
 	// PICC types we can detect. Remember to update PICC_GetTypeName() if you add more.
-	// last value set to 255, hints compiler to use byte instead of default integer, works for arduino ide to save ram and flash
-	enum PICC_Type {
+	// last value set to 0xff, then compiler uses less ram, it seems some optimisations are triggered
+	enum PICC_Type : byte {
 		PICC_TYPE_UNKNOWN		,
 		PICC_TYPE_ISO_14443_4	,	// PICC compliant with ISO/IEC 14443-4 
 		PICC_TYPE_ISO_18092		, 	// PICC compliant with ISO/IEC 18092 (NFC)
@@ -283,12 +283,12 @@ public:
 		PICC_TYPE_MIFARE_UL		,	// MIFARE Ultralight or Ultralight C
 		PICC_TYPE_MIFARE_PLUS	,	// MIFARE Plus
 		PICC_TYPE_TNP3XXX		,	// Only mentioned in NXP AN 10833 MIFARE Type Identification Procedure
-		PICC_TYPE_NOT_COMPLETE	= 255	// SAK indicates UID is not complete.
+		PICC_TYPE_NOT_COMPLETE	= 0xff	// SAK indicates UID is not complete.
 	};
 	
 	// Return codes from the functions in this class. Remember to update GetStatusCodeName() if you add more.
-	// last value set to 255, hints compiler to use byte instead of default integer, works for arduino ide to save ram and flash
-	enum StatusCode {
+	// last value set to 0xff, then compiler uses less ram, it seems some optimisations are triggered
+	enum StatusCode : byte {
 		STATUS_OK				,	// Success
 		STATUS_ERROR			,	// Error in communication
 		STATUS_COLLISION		,	// Collission detected
@@ -297,7 +297,7 @@ public:
 		STATUS_INTERNAL_ERROR	,	// Internal error in the code. Should not happen ;-)
 		STATUS_INVALID			,	// Invalid argument.
 		STATUS_CRC_WRONG		,	// The CRC_A does not match
-		STATUS_MIFARE_NACK		= 255	// A MIFARE PICC responded with NAK.
+		STATUS_MIFARE_NACK		= 0xff	// A MIFARE PICC responded with NAK.
 	};
 	
 	// A struct used for passing the UID of a PICC.