Bidirectional communication using edge timing in a signal

A method, comprising, with a slave device:

• receiving a common signal on a signal line between the slave device and a master device, wherein the common signal comprises a series of signal periods, and wherein each signal period of the common signal comprises no more than one first edge of a first type and no more than one second edge of a second type different from the first type;
• and
• in each signal period of the series of signal periods:
• determining information for communication to the master device;
• determining a timing that communicates the information;
• identifying a first edge in the common signal, the first edge generated by the master signal;
• transmitting the slave signal on the signal line, wherein the slave signal includes a second edge at the timing with respect to the first edge such that the common signal includes the first edge having a timing set by the master device and a second edge having a timing that is set by the slave device;
• determining a timing of the first edge with respect to the signal period;
• and
• determining an operational status of the master device based at least on the determined timing of the first edge.

A master device configured to be connected to a slave device by a signal line, the master device comprising:

• master communication circuitry configured to:
• determine an operational status of the master device;
• and
• generate a master signal, wherein the master signal comprises a series of signal periods, and wherein each signal period of the master signal comprises a first edge of a first type, wherein a timing of the first edge in the master signal is based the determined operational status;
• transmit the master signal on the signal line;
• and
• master detection circuitry configured to:
• receive a common signal, wherein each signal period of the common signal includes no more than one first edge of the first type generated by the master device and no more than one second edge of a second type generated by the slave device, wherein the second type is different from the first type;
• for each signal period of the common signal:
• generate a first edge in the common signal by transmitting the master signal on the signal line;
• determine a timing of an immediately subsequent second edge with respect to the first edge;
• and
• determine information being communicated by the slave device based at least on the determined timing of the second edge.

A slave device configured to be connected to a master device by a signal line, wherein the signal line conducts a common signal comprising a series of signal periods, and wherein each signal period of the common signal comprises no more than one first edge of a first type and no more than one second edge of a second type different from the first type;

• the slave device comprising:
• slave detection circuitry configured to:
• for each signal period, determine a timing of the first edge with respect to the signal period;
• and
• determine an operational status of the master device based at least on the determined timing of the first edge;
• and
• slave communication circuitry configured to:
• determine information for communication to the master device;
• determine a timing that communicates the information;
• identify a first edge in the common signal, the first edge generated by the master signal;
• transmit a slave signal on the signal line, wherein the slave signal includes a second edge at the timing with respect to the first edge such that the common signal includes the first edge having a timing set by the master device and a second edge having a timing that is set by the slave device.