Added multi address slave

Added begin and setAddressAndMask warnings if called with mask on a uC without mask support

Author: corna

Diff for: hardware/arduino/avr/libraries/Wire/Wire.cpp

@@ -19,6 +19,7 @@
   Modified 2012 by Todd Krein ([email protected]) to implement repeated starts
   Modified 2014 by Nicola Corna ([email protected])
     Moved pullups enable from twi.c to Wire.cpp
+    Added multi address slave
 */
 
 extern "C" {
@@ -83,6 +84,32 @@ void TwoWire::begin(int address)
   begin((uint8_t)address);
 }
 
+void TwoWire::begin(uint8_t address, uint8_t mask)
+{
+#ifdef TWAMR
+  twi_setAddressAndMask(address, mask);
+#else
+  twi_setAddress(address);      //Just to show the function warning only once
+#endif
+  twi_attachSlaveTxEvent(onRequestService);
+  twi_attachSlaveRxEvent(onReceiveService);
+  begin();
+}
+
+void TwoWire::begin(int address, int mask)
+{
+#ifdef TWAMR
+  begin((uint8_t)address, (uint8_t)mask);
+#else
+  begin((uint8_t)address);            //Just to show the function warning only once
+#endif
+}
+
+uint8_t TwoWire::slaveAddress()
+{
+  return twi_slaveAddress();
+}
+
 void TwoWire::setClock(uint32_t frequency)
 {
   TWBR = ((F_CPU / frequency) - 16) / 2;

Diff for: hardware/arduino/avr/libraries/Wire/Wire.h

@@ -17,6 +17,8 @@
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
   Modified 2012 by Todd Krein ([email protected]) to implement repeated starts
+  Modified 2014 by Nicola Corna ([email protected])
+    Added multi address slave
 */
 
 #ifndef TwoWire_h
@@ -49,6 +51,14 @@ class TwoWire : public Stream
     void begin();
     void begin(uint8_t);
     void begin(int);
+#ifdef TWAMR
+    void begin(uint8_t, uint8_t);
+    void begin(int, int);
+#else
+    void begin(uint8_t, uint8_t) __attribute__((warning("I2C address masking is unsupported on this microcontroller. Mask 0x00 will be used.")));
+    void begin(int, int) __attribute__((warning("I2C address masking is unsupported on this microcontroller. Mask 0x00 will be used.")));
+#endif
+    uint8_t slaveAddress();
     void setClock(uint32_t);
     void beginTransmission(uint8_t);
     void beginTransmission(int);

Diff for: hardware/arduino/avr/libraries/Wire/keywords.txt

@@ -11,6 +11,7 @@
 #######################################
 
 begin	KEYWORD2
+slaveAddress	KEYWORD2
 setClock	KEYWORD2
 beginTransmission	KEYWORD2
 endTransmission	KEYWORD2

Diff for: hardware/arduino/avr/libraries/Wire/utility/twi.c

@@ -20,13 +20,13 @@
   Modified 2014 by Nicola Corna ([email protected])
     Moved pullups enable from twi.c to Wire.cpp
     Updated deprecated include <compat/twi.c>
+    Added multi address slave
 */
 
 #include <math.h>
 #include <stdlib.h>
 #include <stdbool.h>
 #include <inttypes.h>
-#include <avr/io.h>
 #include <avr/interrupt.h>
 #include <util/twi.h>
 
@@ -61,6 +61,10 @@ static volatile uint8_t twi_rxBufferIndex;
 
 static volatile uint8_t twi_error;
 
+#ifdef TWAMR
+static volatile uint8_t twi_lastSlaveAddress;
+#endif
+
 /* 
  * Function twi_init
  * Desc     readys twi pins and sets twi bitrate
@@ -86,11 +90,16 @@ void twi_init(void)
 
   // enable twi module, acks, and twi interrupt
   TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA);
+  
+#ifdef TWAMR
+  // initialize to 0
+  twi_lastSlaveAddress = 0x00;
+#endif
 }
 
 /* 
- * Function twi_slaveInit
- * Desc     sets slave address and enables interrupt
+ * Function twi_setAddress
+ * Desc     set the slave address
  * Input    none
  * Output   none
  */
@@ -100,6 +109,40 @@ void twi_setAddress(uint8_t address)
   TWAR = address << 1;
 }
 
+/* 
+ * Function twi_setAddressAndMask
+ * Desc     sets slave address and slave address mask
+ * Input    address: slave address
+ * 	    mask: slave address mask
+ * Output   none
+ */
+void twi_setAddressAndMask(uint8_t address, uint8_t mask)
+{
+  // set twi slave address (skip over TWGCE bit)
+  TWAR = address << 1;
+#ifdef TWAMR
+  //set twi slave address mask
+  TWAMR = mask << 1;
+#endif
+}
+
+/* 
+ * Function twi_slaveAddress
+ * Desc     return the last called slave address
+ * Input    none
+ * Output   the slave address
+ */
+uint8_t twi_slaveAddress(void)
+{
+  //If address masking is not supported, returns the only address
+  //supported (saved in TWAR)
+#ifdef TWAMR
+  return twi_lastSlaveAddress;
+#else
+  return TWAR >> 1;
+#endif
+}
+
 /* 
  * Function twi_readFrom
  * Desc     attempts to become twi bus master and read a
@@ -441,6 +484,10 @@ ISR(TWI_vect)
     case TW_SR_ARB_LOST_GCALL_ACK: // lost arbitration, returned ack
       // enter slave receiver mode
       twi_state = TWI_SRX;
+#ifdef TWAMR
+      // save the current TWDR (slave address)
+      twi_lastSlaveAddress = TWDR >> 1;
+#endif
       // indicate that rx buffer can be overwritten and ack
       twi_rxBufferIndex = 0;
       twi_reply(1);
@@ -482,6 +529,10 @@ ISR(TWI_vect)
     case TW_ST_ARB_LOST_SLA_ACK: // arbitration lost, returned ack
       // enter slave transmitter mode
       twi_state = TWI_STX;
+#ifdef TWAMR
+      // save the current TWDR (slave address)
+      twi_lastSlaveAddress = TWDR >> 1;
+#endif
       // ready the tx buffer index for iteration
       twi_txBufferIndex = 0;
       // set tx buffer length to be zero, to verify if user changes it

Diff for: hardware/arduino/avr/libraries/Wire/utility/twi.h

@@ -15,13 +15,17 @@
   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+  
+  Modified 2014 by Nicola Corna ([email protected])
+    Added multi address slave
 */
 
 #ifndef twi_h
 #define twi_h
 
   #include <inttypes.h>
-
+  #include <avr/io.h>
+  
   //#define ATMEGA8
 
   #ifndef TWI_FREQ
@@ -40,6 +44,12 @@
 
   void twi_init(void);
   void twi_setAddress(uint8_t);
+#ifdef TWAMR
+  void twi_setAddressAndMask(uint8_t, uint8_t);
+#else
+  void twi_setAddressAndMask(uint8_t, uint8_t) __attribute__((warning("I2C address masking is unsupported on this microcontroller. Mask 0x00 will be used.")));
+#endif
+  uint8_t twi_slaveAddress(void);
   uint8_t twi_readFrom(uint8_t, uint8_t*, uint8_t, uint8_t);
   uint8_t twi_writeTo(uint8_t, uint8_t*, uint8_t, uint8_t, uint8_t);
   uint8_t twi_transmit(const uint8_t*, uint8_t);