Always clean up previous I2C object before new to avoid leaking memory

Author: waynepiekarski

libraries/Wire/Wire.cpp

@@ -28,11 +28,13 @@ arduino::MbedI2C::MbedI2C(int sda, int scl) : _sda(digitalPinToPinName(sda)), _s
 arduino::MbedI2C::MbedI2C(PinName sda, PinName scl) : _sda(sda), _scl(scl), usedTxBuffer(0), slave_th(osPriorityNormal, 2048, nullptr, "I2CSlave") {}
 
 void arduino::MbedI2C::begin() {
+	end();
 	master = new mbed::I2C(_sda, _scl);
 }
 
 void arduino::MbedI2C::begin(uint8_t slaveAddr) {
 #ifdef DEVICE_I2CSLAVE
+	end();
 	slave = new mbed::I2CSlave((PinName)_sda, (PinName)_scl);
 	slave->address(slaveAddr << 1);
 	slave_th.start(mbed::callback(this, &arduino::MbedI2C::receiveThd));