US Patent 9690725 Camera control interface extension with in-band interrupt

Master and slave devices may be coupled to a control data bus. A method includes controlling data transmissions over a bus from a master device, where data bits are transcoded into symbols for transmission across two lines of the bus and a clock signal is embedded within symbol transitions of the data transmissions, and providing an interrupt period, during which one or more slave devices coupled to the bus can assert an interrupt request on a first line of the bus, within part of a heartbeat transmission by the master device over the first line and a second tine of the bus. The interrupt request may be an indicator that the asserting slave device wishes to request some action by the master device.