US Patent 8433838 Remote multiplexing devices on a serial peripheral interface bus

A serial peripheral interface (SPI) bus and method of communicating over an SPI bus to multiple slave devices without requiring the master device to have an independent slave select pin for each slave device. The SPI bus comprises an SPI master device coupled to an SPI multiplex slave device and a plurality of SPI non-multiplex slave devices. The SPI multiplex slave device includes an independent slave select (SS) output pin coupled to each one of the SPI non-multiplex slave devices for sending an activation signal to a selected SPI slave device in response to receiving a command from the master device containing identification of the selected SPI slave device.