The PCA9547 is an octal bidirectional translating multiplexer controlled by the I2C-bus.
The SCL/SDA upstream pair fans out to eight downstream pairs, or channels. Only one
SCx/SDx channel can be selected at a time, determined by the contents of the
programmable control register. The device powers up with Channel 0 connected, allowing
immediate communication between the master and downstream devices on that channel.
