Update Wire.cpp

Adds a check to verify if the port had been already enabled, and only in that case disables/re-enables the port. This also solves the issue of setClock being called after begin(), but doesn't not enable the port if begin() had not been called yet.

Author: victorpv

STM32F1/libraries/Wire/Wire.cpp

@@ -97,8 +97,10 @@ void HardWire::setClock(uint32_t frequencyHz)
 			dev_flags &= ~I2C_FAST_MODE;// clear FAST_MODE bit
 			break;
 	}
-	i2c_disable(sel_hard);
-	i2c_master_enable(sel_hard, dev_flags);
+	if (sel_hard->regs->CR1 & I2C_CR1_PE){
+	    i2c_disable(sel_hard);
+	    i2c_master_enable(sel_hard, dev_flags);
+	}
 }
 
 HardWire Wire(1);