Moved macros that are not part of the twi API from twi.h to twi.cpp.

Replaced TWI_STATE preprocessor macro by enum TWI_STATE.
Added #pragma once in twi.h.

Author: dac1e

libraries/Wire/src/utility/twi.cpp

@@ -40,6 +40,22 @@
 #include "pins_arduino.h"
 #include "twi.h"
 
+#ifndef TWI_FREQ
+#define TWI_FREQ 100000L
+#endif
+
+#ifndef TWI_BUFFER_LENGTH
+#define TWI_BUFFER_LENGTH 32
+#endif
+
+enum TWI_STATE {
+  TWI_READY = 0,
+  TWI_MRX   = 1,
+  TWI_MTX   = 2,
+  TWI_SRX   = 3,
+  TWI_STX   = 4,
+};
+
 static volatile uint8_t twi_state;
 static volatile uint8_t twi_slarw;
 static volatile uint8_t twi_sendStop;			// should the transaction end with a stop

libraries/Wire/src/utility/twi.h

@@ -19,27 +19,15 @@
   Modified 2020 by Greyson Christoforo (grey@christoforo.net) to implement timeouts
 */
 
+#pragma once
+
 #ifndef twi_h
 #define twi_h
 
   #include <inttypes.h>
 
   //#define ATMEGA8
 
-  #ifndef TWI_FREQ
-  #define TWI_FREQ 100000L
-  #endif
-
-  #ifndef TWI_BUFFER_LENGTH
-  #define TWI_BUFFER_LENGTH 32
-  #endif
-
-  #define TWI_READY 0
-  #define TWI_MRX   1
-  #define TWI_MTX   2
-  #define TWI_SRX   3
-  #define TWI_STX   4
-  
   void twi_init(void);
   void twi_disable(void);
   void twi_setAddress(uint8_t);
@@ -56,4 +44,4 @@
   void twi_handleTimeout(bool);
   bool twi_manageTimeoutFlag(bool);
 
-#endif
+#endif // #ifndef twi_h