Token bus communication system

A token bus communication system comprising a multiplicity of nodes connected by a common bus, wherein each of the multiplicity of nodes is organized:)

• (i) when in possession of a token and having data to transmit, to transmit a ‘token & data’ packet including a payload and having a header including a first address field for identifying which node is to receive the token and a second address field for identifying which node is to receive the payload;
• (ii) when in possession of a token and having no data to transmit, to transmit a ‘token only’ packet having said first and second address fields, wherein said first address field identifies which node is to receive the token and said second address field identifies none of the said nodes;
• and
• (iii) to receive from other nodes ‘token & data’ and ‘token only’ packets and to determine whether a token and/or data is destined for that node;
• wherein all said packets have a common frame structure including a command field which has a first value for a ‘token & data’ packet and a second value for a ‘token only’ packet;
• and wherein:
• (a) each of the nodes in the multiplicity thereof is operative to have a master state in which it determines the identity of all of the other nodes in operative connection with the common bus and broadcasts to all the other nodes a sequence table which specifies an order for the reception of the token;
• and
• (b) each of the nodes in the multiplicity thereof is operative to have at least one run state in which, in response to reception of the token, it transmits the token immediately to the node next following it in the sequence table.

A token bus communication system comprising a multiplicity of nodes connected by a common bus, wherein each of the multiplicity of nodes is organized:

• (i) when in possession of a token and having data to transmit, to transmit a ‘token & data’ packet including a payload and having a header including a first destination address field for identifying which node is to receive the token, a second destination address field for identifying which node is to receive the token and a command field identifying this packet as a ‘token & data’ packet;
• (ii) when in possession of a token and having no data to transmit, to transmit a ‘token only’ packet having a header including a destination address field identifying which node is to receive the token and a command field identifying this packet as a ‘token only’ packet;
• and
• (iii) to receive from other nodes ‘token & data’ and ‘token only’ packets and to determine whether a token and/or data is destined for that node;
• and wherein:
• (a) each of the nodes in the multiplicity thereof is operative to have a master state in which it determines the identity of all of the other nodes in operative connection with the common bus and broadcasts to all said other nodes a sequence table which specifies an order for the reception of the token;
• and
• (b) each of the nodes in the multiplicity thereof is operative to have at least one run state in which, in response to reception of the token, it transmits the token immediately to the node next following it in the sequence table.