I2C/SPI on the BeagleBone expansion connector
I2C and SPI are two common serial buses used to interface with many commonly used peripherals. Using these buses while interfacing is more advanced than a simple beginner's task; beginners should be aware of them. In our exercises, although we looked at I2C, we focused on what is on the board itself.
Inter-Integrated Circuit
Inter-Integrated Circuit (I2C) is a two-wire serial bus interface. This interface defines a full protocol to allow different devices on the bus to be identified with addresses. Different combinations of the states of two wires are used to identify different parts of the protocol. When using I2C to interface from the BeagleBone to an I2C device, the key things to be aware of are as follows:
I2C signals are open collector. This allows multiple devices to be connected in parallel. However, this requires two resistors, roughly from 1000 to 4700 Ohms that connect each of the I2C signals to 3.3V. Open collector means each device...
