Wire Examples based on AVR ones of the same name (#5713)

* Wire Examples based on AVR ones of the same name

* Overload for begin(), change in callback arg from int to size_t

* Update master_reader.ino

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* Update master_writer.ino

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* Update slave_receiver.ino

Remove warning

* Update slave_receiver.ino

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Author: devyte

libraries/Wire/Wire.cpp

@@ -51,7 +51,7 @@ uint8_t TwoWire::txBufferLength = 0;
 
 uint8_t TwoWire::transmitting = 0;
 void (*TwoWire::user_onRequest)(void);
-void (*TwoWire::user_onReceive)(int);
+void (*TwoWire::user_onReceive)(size_t);
 
 static int default_sda_pin = SDA;
 static int default_scl_pin = SCL;
@@ -69,6 +69,16 @@ void TwoWire::begin(int sda, int scl){
   flush();
 }
 
+void TwoWire::begin(int sda, int scl, uint8_t address){
+  default_sda_pin = sda;
+  default_scl_pin = scl;
+  twi_setAddress(address);
+  twi_init(sda, scl);
+  twi_attachSlaveTxEvent(onRequestService);
+  twi_attachSlaveRxEvent(onReceiveService);
+  flush();
+}
+
 void TwoWire::pins(int sda, int scl){
   default_sda_pin = sda;
   default_scl_pin = scl;
@@ -255,7 +265,7 @@ void TwoWire::onRequestService(void)
 	user_onRequest();
 }
 
-void TwoWire::onReceive( void (*function)(int) ) {
+void TwoWire::onReceive( void (*function)(size_t) ) {
   user_onReceive = function;
 }
 

libraries/Wire/Wire.h

@@ -45,12 +45,13 @@ class TwoWire : public Stream
 
     static uint8_t transmitting;
     static void (*user_onRequest)(void);
-    static void (*user_onReceive)(int);
+    static void (*user_onReceive)(size_t);
     static void onRequestService(void);
     static void onReceiveService(uint8_t*, size_t);
   public:
     TwoWire();
     void begin(int sda, int scl);
+    void begin(int sda, int scl, uint8_t address);    
     void pins(int sda, int scl) __attribute__((deprecated)); // use begin(sda, scl) in new code
     void begin();
     void begin(uint8_t);
@@ -75,7 +76,7 @@ class TwoWire : public Stream
     virtual int read(void);
     virtual int peek(void);
     virtual void flush(void);
-    void onReceive( void (*)(int) );
+    void onReceive( void (*)(size_t) );
     void onRequest( void (*)(void) );
 
     inline size_t write(unsigned long n) { return write((uint8_t)n); }

libraries/Wire/examples/master_reader/master_reader.ino

@@ -0,0 +1,37 @@
+// Wire Master Reader
+// by devyte
+// based on the example of the same name by Nicholas Zambetti <http://www.zambetti.com>
+
+// Demonstrates use of the Wire library
+// Reads data from an I2C/TWI slave device
+// Refer to the "Wire Slave Sender" example for use with this
+
+// This example code is in the public domain.
+
+
+#include <Wire.h>
+#include <PolledTimeout.h>
+
+#define SDA_PIN 4
+#define SCL_PIN 5
+const int16_t I2C_MASTER = 0x42;
+const int16_t I2C_SLAVE = 0x08;
+
+void setup() {
+  Serial.begin(115200);  // start serial for output
+  Wire.begin(SDA_PIN, SCL_PIN, I2C_MASTER);        // join i2c bus (address optional for master)
+}
+
+void loop() {
+  using periodic = esp8266::polledTimeout::periodic;
+  static periodic nextPing(1000);
+
+  if (nextPing) {
+    Wire.requestFrom(I2C_SLAVE, 6);    // request 6 bytes from slave device #8
+
+    while (Wire.available()) { // slave may send less than requested
+      char c = Wire.read(); // receive a byte as character
+      Serial.print(c);         // print the character
+    }
+  }
+}

libraries/Wire/examples/master_writer/master_writer.ino

@@ -0,0 +1,38 @@
+// Wire Master Writer
+// by devyte
+// based on the example of the same name by Nicholas Zambetti <http://www.zambetti.com>
+
+// Demonstrates use of the Wire library
+// Writes data to an I2C/TWI slave device
+// Refer to the "Wire Slave Receiver" example for use with this
+
+// This example code is in the public domain.
+
+
+#include <Wire.h>
+#include <PolledTimeout.h>
+
+#define SDA_PIN 4
+#define SCL_PIN 5
+const int16_t I2C_MASTER = 0x42;
+const int16_t I2C_SLAVE = 0x08;
+
+void setup() {
+  Wire.begin(SDA_PIN, SCL_PIN, I2C_MASTER); // join i2c bus (address optional for master)
+}
+
+byte x = 0;
+
+void loop() {
+  using periodic = esp8266::polledTimeout::periodic;
+  static periodic nextPing(1000);
+
+  if (nextPing) {
+    Wire.beginTransmission(I2C_SLAVE); // transmit to device #8
+    Wire.write("x is ");        // sends five bytes
+    Wire.write(x);              // sends one byte
+    Wire.endTransmission();    // stop transmitting
+
+    x++;
+  }
+}

libraries/Wire/examples/slave_receiver/slave_receiver.ino

@@ -0,0 +1,41 @@
+// Wire Slave Receiver
+// by devyte
+// based on the example by Nicholas Zambetti <http://www.zambetti.com>
+
+// Demonstrates use of the Wire library
+// Receives data as an I2C/TWI slave device
+// Refer to the "Wire Master Writer" example for use with this
+
+// This example code is in the public domain.
+
+
+#include <Wire.h>
+
+#define SDA_PIN 4
+#define SCL_PIN 5
+
+const int16_t I2C_MASTER = 0x42;
+const int16_t I2C_SLAVE = 0x08;
+
+void setup() {
+  Serial.begin(115200);           // start serial for output
+
+  Wire.begin(SDA_PIN, SCL_PIN, I2C_SLAVE); // new syntax: join i2c bus (address required for slave)
+  Wire.onReceive(receiveEvent); // register event
+}
+
+void loop() {
+}
+
+// function that executes whenever data is received from master
+// this function is registered as an event, see setup()
+void receiveEvent(size_t howMany) {
+
+  (void) howMany;
+  while (1 < Wire.available()) { // loop through all but the last
+    char c = Wire.read(); // receive byte as a character
+    Serial.print(c);         // print the character
+  }
+  int x = Wire.read();    // receive byte as an integer
+  Serial.println(x);         // print the integer
+}

libraries/Wire/examples/slave_sender/slave_sender.ino

@@ -0,0 +1,32 @@
+// Wire Slave Sender
+// by devyte
+// based on the example of the same name by Nicholas Zambetti <http://www.zambetti.com>
+
+// Demonstrates use of the Wire library
+// Sends data as an I2C/TWI slave device
+// Refer to the "Wire Master Reader" example for use with this
+
+// This example code is in the public domain.
+
+
+#include <Wire.h>
+
+#define SDA_PIN 4
+#define SCL_PIN 5
+const int16_t I2C_MASTER = 0x42;
+const int16_t I2C_SLAVE = 0x08;
+
+void setup() {
+  Wire.begin(SDA_PIN, SCL_PIN, I2C_SLAVE);                // join i2c bus with address #8
+  Wire.onRequest(requestEvent); // register event
+}
+
+void loop() {
+}
+
+// function that executes whenever data is requested by master
+// this function is registered as an event, see setup()
+void requestEvent() {
+  Wire.write("hello\n"); // respond with message of 6 bytes
+  // as expected by master
+}