One day you write that the macro MSBFIRST isn’t defined, and before you can go to press, it’s defined right there in Arduino.h. Great stuff! The I2C (“Wire”) library has also gotten the ...

The need for a second UART port ( and one that is not shared with USB) on the Arduino Uno is so great that the “SoftwareSerial” library in included ... A second I2C bus: Your address clashes ...