Daisy-chained serial bus for multiple small footprint devices

A method for data transfer, comprising;

• providing a first node connected to a bus to communicate bidirectionally;
• and
• providing a plurality of second nodes connected in series to the bus, each of the plurality of second nodes lacking an internal clock and having fixed pads including a power pad, a ground pad, signal pads to transfer a data frame, return data pads for a return signal, select pads for a selection signal and clock pads for a clock signal, wherein each of the signal pads, the return data pads, the select pads and the clock pads comprise respective input pads and output pads,
• wherein each of the plurality of second nodes is indexed by a hop count in the data frame, the hop count being incremented each time the data frame is transferred from the first node to each respective one of the plurality of seconds nodes having six pad types in topological order,
• wherein each of the plurality of second nodes is selectable using an addressing mode defined by a combination of the hop count, a mask field and an address field in the data frame,
• wherein the signal pads are used for data transfer of the data frame in a selected node mode controlled by a combination of the selection signal, the clock signal and the return signal, and
• wherein the addressing mode comprises:
• a single node addressing mode defined by any of the hop count and the address field,
• a group of nodes addressing mode defined by a combination of any of (i) the hop count and the mask field and (ii) the address field and the mask field, and
• a broadcasting addressing mode that uses each of the hop count. the address field, and the mask field.

An apparatus for data transfer, comprising;

• a first node connected to a bus to communicate bidirectionally;
• and
• a plurality of second nodes connected in series to the bus, each of the plurality of second nodes lacking an internal clock and having fixed pads including a power pad, a ground pad, signal pads to transfer a data frame, return data pads for a return signal, select pads for a selection signal and clock pads for a clock signal, wherein each of the signal pads, the return data pads, the select pads and the clock pads comprise respective input pads and output pads,
• wherein each of the plurality of second nodes is indexed by a hop count in the data frame, the hop count being incremented each time the data frame is transferred from the first node to each respective one of the plurality of seconds nodes having six pad types in topological order,
• wherein each of the plurality of second nodes is selectable using an addressing mode defined by a combination of the hop count, a mask field and an address field in the data frame,
• wherein the signal pads are used for data transfer of the data frame in a selected node mode selected from:
• a first node mode for indicating that the signal pins are used for data transfer, responsive to the selection signal being active,
• a second node mode for resetting the plurality of second nodes by the first node, responsive to the selection signal being inactive and the clock signal being active, and
• a third node mode for generating an interrupt by any of the plurality of second nodes, responsive to the selection signal being inactive and the return signal being active, and
• wherein the addressing mode comprises:
• a single node addressing mode defined by any of the hop count and the address field,
• a group of nodes addressing mode defined by a combination of any of (i) the hop count and the mask field and (ii) the address field and the mask field, and
• a broadcasting addressing mode that uses each of the hop count. the address field, and the mask field.