Modified I2C api to work with NRF's dynamic pin asignment.

Dependents:   Seed_Barometer_Sensor_custom_I2C_lib

Note that the only changes are in the constructor. I tried extending the original I2C class, but could not find away to avoid the i2c_init from being called there.

Revision:
2:9d9fc94594e3
Parent:
0:3d97d631d8dd
--- a/I2CX.cpp	Wed Oct 22 10:32:42 2014 +0000
+++ b/I2CX.cpp	Wed Oct 22 11:18:05 2014 +0000
@@ -37,6 +37,8 @@
     _i2c.sda = sda;
     _i2c.scl = scl;
     
+    i2c_reset(&_i2c);
+    
     // Used to avoid unnecessary frequency updates
     _owner = this;
 }