Single wire bus interface for multidrop applications

A single wire communications protocol enabling a master device to control communications for a multidrop circuit over a single wire bus interface, the multidrop circuit suitable arranged to couple the master device and a plurality of slave devices via the single wire bus interface, each slave device being assigned a unique window of response, the protocol comprising instructions for:

• initiating a timing sequence by transmitting a start command on the single wire bus interface;
• processing data received during each window of response including interpreting data received during each unique window of response as corresponding to the particular slave device assigned to that unique window of response;
• and
• delaying each window of response with conversion function circuitry which includes a plurality of flip-flop devices arranged to delay a response signal for each slave device until each slave devices unique window of response.

An electrical device suitable for use as a slave device in a multidrop application, the multidrop application arranged for data communications between a master device and multiple slave devices over a single wire bus, each electrical device being assigned a different response time window, the electrical device comprising:

• application circuitry providing state information for the electrical device;
• an input/output pin suitable for making an electrical coupling external to the electrical device;
• and
• a single wire bus interface coupled to the input/output pin and the application circuitry, the single wire bus interface having conversion function circuitry defining a specific response time window for the electronic device, the single wire bus responsive to a start signal received on the input/output pin to generate a response signal within the specific response time window, the response signal indicative of the state information for the electrical device;
• wherein the conversion function circuitry includes a plurality of flip-flop devices, the flip-flop devices arranged to delay the response signal until the specific response time window.

A multidrop circuit comprising:

• a single wire bus;
• a master device coupled to the single wire bus;
• a first slave device coupled to the single wire bus and assigned a specific response time window, the first slave device including:
• application circuitry providing state information for the slave device;
• and
• a single wire bus interface coupled to the single wire bus and the application circuitry, the single wire bus interface having conversion function circuitry defining the specific response time window for the electronic device, the single wire bus interface responsive to a start signal transmitted on the single wire bus to generate a response signal within the specific response time window, the response signal indicative of the state information for the slave device;
• wherein the conversion function circuitry includes a plurality of flip-flop devices, the flip-flop devices arranged to delay the response signal until the specific response time window.