Patent ID: 8185678

Claim:
A method of operating a data bus controller coupled to a bus via a transceiver circuit, comprising: monitoring the bus for presence of a device while the bus controller and the transceiver circuit are in a first state; wherein the transceiver circuit does not transmit data over the bus while in the first state; transitioning from the first state to a second state in response to presence of a device on the bus; while the bus controller is in the second state, opening, configuring and monitoring communications with devices coupled to the bus, and further communicating with the devices at two or more transmission rates including a first rate that is lower than a second rate; transitioning the bus controller and transceiver circuit from the second state to a third state in response to conditions on the bus indicating that all communications on the bus have ceased or need to be stopped; and closing communication channels and configuring the controller and transceiver circuit to operate at the first transmission rate while the bus controller and transceiver circuit are in the third state, and transitioning the bus controller into the first state in response to completing configuration of the transmission rate; wherein configuring the controller to operate at the first transmission rate includes: detecting a current transmission rate; and setting the transmission rate to the first rate if a higher rate is detected; wherein setting the transmission rate of the controller includes: sending a control signal from the controller to the transceiver circuit; and waiting to set the transmission rate until the transceiver circuit sends a signal confirming configuration of the transmission rate has completed.