Time multiplex system for transmitting information between vehicle components

• US 4,780,620 A
• Filed: 06/23/1987
• Issued: 10/25/1988
• Est. Priority Date: 05/07/1987
• Status: Expired due to Fees

• Current Assignee: Töcksfors Verkstads AB
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Hogberg, Bo Arne G., Ahs, Inge W.
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US07/065,368
• Time in Patent Office: 490 Days
• Field of Search: 307/9, 307/10 R, 307/10 LS, 307/38, 340/52 F, 340/825.21, 340/825.2, 340/870.15, 364/424, 370/85
• US Class Current: 307/10.1
• CPC Class Codes: H04J 3/0647 Synchronisation among TDM nodes
• CPC Class Codes: H04L 12/40 Bus networks

Abstract

The invention relates to a system for time multiplex transmission of analogue and digital information between components in a vehicle. The system includes a synchronizing unit (1) and a plurality of transmission units (2A, 2B, . . . , 2H) connected to a bus (B) with at least three bus conductors (BC1, BC2, BC3, BC4) for power supply and transmission of signals between the units. The synchronizing unit and transmission units may assume either an active state or a standby state. In its active state the synchronizing unit sends timing signals on a second of the bus conductors (BC2) for synchronizing the transmission units, and for definition of a plurality of time slots on a first of the bus conductors (BC1). In its active state, each of the transmission units can send and/or receive information selectively in at least one time slot on the first bus conductor (BC1). The synchronizing unit does not send any time controlling signals in its standby state. In its standby state a transmission unit lacks the ability of selectively receiving information from the first bus conductor or selectively sending information in a given time slot on the first bus conductor. Different criteria for changing between active state and a standby state apply to different transmission units.

Claims

1. A system for time multiplex transmission of information between a plurality of vehicle components, comprising:

a bus having a first bus line and a second bus line;

a synchronizing unit, coupled to said bus, including

means for generating a plurality of control signals on said second bus line, for defining a plurality of time slots on the bus, when said synchronizing unit is in a synchronizing unit active state,

means for disabling said generating means from generating at least some of said plurality of control signals when said synchronizing unit is in a synchronizing unit standby state, and

means for placing said synchronizing unit in said synchronizing unit active state in response to a signal on said first bus line;

a first transmission unit, coupled to said bus, including means for transferring information in at least one direction between the first bus line and a vehicle component in a first active state assumed in response to receipt of predetermined control signals from said synchronizing unit; and

a second transmission unit, coupled to said bus, including

means for transferring information in at least one direction between the first bus line and a vehicle equipment in a second active state assumed in response to receipt of information signals in at least one predetermined time slot on the first bus line, and

means for causing said second transmission unit to assume a standby state in response to an absence of information signals in at least one predetermined time slot on the first bus line.

2. A system in claimed in claim 1, in which the synchronizing unit further includes means for causing said synchronizing unit to go from said synchronizing unit active state to said synchronizing unit standby state in response to an absence of information signals in one or a plurality of predetermined time slots on the first bus line, irrespective of the presence of information signals in one or more of the other time slots on the first bus line.

3. A system as claimed in claim 1, in which the synchronizing unit includes means for causing said synchronizing unit to send intermittently on the second bus line only a limited control signal, which defines only a small number of time slots on the bus.

4. A system as claimed in claim 1, in which one of said first transmission unit and second transmission unit includes means for sending analogue information to another transmission unit when said one of said first and second transmission units is in its active state.

5. A system as claimed in claim 1, in which each transmission unit includes means for sending one of a single analogue sampled potential and a single binary signal per time slot on the first bus line, and in which each transmission unit further includes means for receiving one of a single analogous sampled potential and a single binary signal per time slot on the first bus line.

6. A system as claimed in claim 1, in which each transmission unit includes means for transferring information in at least three and at most five time slots on the first bus line, and in that each transmission unit includes means for individual determination of the at least three and at most five time slots.

7. A system as claimed in claim 1, in which each transmission unit includes means for sending information on the first bus line solely during one of the first and second half of at least one time slot and for receiving information from the first bus line solely during the other of the first and second half of said at least one time slot.

8. A system for time multiplex transmission of information between vehicle components, said system including a first and a second synchronizing units and a plurality of similar transmission units connected to a bus having at least three bus conductors for power supply and transmission of signals between the units;

said first synchronizing unit including means for enabling it to assume an active state in which it sends timing signals on the bus for synchronizing the transmission units, and for defining a plurality of time slots on the bus, said first synchronizing unit including means for enabling it to assume a standby state in which it does not send timing signals, said first synchronizing unit further including means for transfer from its standby state to its active state when signals from a transmission unit have been present on the first bus conductor for a comparatively short time, simultaneously as timing signals have not been present on the second bus conductor during that short time;

said second synchronizing unit including means for enabling it to assume an active state in which it sends timing signals on the bus, said second synchronizing unit further including means for enabling it to assume a standby state in which it does not send timing signals on the bus, said second synchronizing unit further including means for transfer from its standby state to its active state not until signals from a transmission unit have been present on the first bus conductor for a comparatively long time, simultaneously as timing signals have not been present on the second bus conductor during that long time;

said transmission units each having at least one of an input and an output for tranferring information in at least one direction between a vehicle component and the first bus conductor, said transmission units each comprising means for enabling them to assume an active state in which a given transmission unit receives timing signals from either one of said synchronizing units and selectively transfers in a predetermined time slot on the first bus conductor information signals in correspondence to information on and said one of an input and output information in correspondence to information signals appearing in a predetermined time slot (TSN) on the first bus conductor, said transmission units each including means for enabling them to assume a standby state in which a given transmission unit does not selectively transfer information in correspondence to any information signals in any given time slot on the first bus conductor;

a first group of said transmission units being controlled to transfer from their standby state to their active state on the presence of the timing signals on the bus;

each synchronizing unit including means for sending its time controlling signals defining the time slots on a second bus conductor separated from the the first bus conductor and a second group of transmission units being controlled to transfer from their standby state to their active state on the presence of information signals in at least one predetermined time slot on the first bus conductor, said second group being controlled to transfer from their active state to their standby state in response to an absence of information signals in at least one predetermined time slot on the first bus conductor.

9. A system as claimed in claim 8, in which each of the first and the second synchronizing units includes means for changing its active state to its standby state in response to the absence of information signals in one or a plurality of predetermined time slots on the first bus conductor, irrespective of the presence of information signals in at least one of the other time slots on the first bus conductor.

10. A system as claimed in claim 8, in which at least one transmission unit in its active state is adapted for transmission of analogue information from an input to another transmission unit via the first bus conductor.

11. A system as claimed in claim 8, in which each transmission unit includes means for sending at least one of a single analogue sampled potential and a single binary signal per time slot on the first bus conductor, and in that each transmission unit includes means for receiving at least one of a single analogue sampled potential and a single binary signal per time slot on the first bus conductor.

12. A system as claimed in claim 8, in which each transmission unit includes means for enabling it to transfer information in at least three and at most five time slots in succession on the first bus conductor, and in which each transmission unit includes means for selecting its time slots independent of the time slots selected by the remaining transmission units.

13. A system as claimed in claim 8, in which each transmission unit is controllable to transfer information between a vehicle component and the first bus conductor in a first direction solely during the first half of at least one time slot and to transfer information between a vehicle component and the first bus conductor in a second direction solely during the second half of this at least one time slot.

14. A system for time multiplex transmission of information between vehicle components, said system including a synchronizing unit and a plurality of substantially similar transmission units connected to a bus having at least three bus conductors for power supply and transmission of signals between the units;

said synchronizing unit including means for detecting signals from a transmission unit on a first of the bus conductors and means for generating timing signals on a second of the bus conductors;

said synchronizing unit including means for enabling it to assume an active mode of operation in which it regularly sends timing signals on the second bus conductor in the bus for synchronizing the transmission units, and for defining a plurality of time slots on the bus, said synchronizing unit including means for enabling it to assume a standby mode of operation in which it sends timing signals on the bus at most intermittently, the synchronizing unit including means for going from its standby mode of operation to its active mode when signals from a transmission unit have been present on the first bus conductor at least for a comparatively short time, simultaneously as timing signals have not been present on the second bus conductor at least for the same comparatively short time;

said transmission units each having at least one of an input for transferring information between a vehicle component and the first bus conductor, said transmission units each including means for detecting said timing signals on the second bus conductor, said transmission units each including means for enabling them to assume an active mode of operation in which a given transmission unit receives timing signals from said synchronizing unit and selectively transfers in a predetermined time slot on the first bus conductor information signals in correspondence to information on said one of an input and output information in correspondence to information signals appearing in a predetermined time slot on the first bus conductor, said transmission units each including means for enabling them to assume a standby mode of operation in which a given transmission unit does not selectively transfer information in correspondence to any information signals in any given time slot on the first bus conductor, said transmission units each having an activating input for individual control of the conditions under which the transmission unit shall go from its standby mode of operation to said active mode;

a first group of said transmission units being controlled to go from their standby mode of operation to their active mode on the presence of the timing signals on the bus; and

a second group of said transmission units being controlled to go from their standby mode of operation to their active mode on the presence of information signals in at least one predetermined time slot on the first bus conductor, said second group being controlled to go from their active mode to their standby mode of operation in response to an absence of information signals in at least one predetermined time slot on the first bus conductor.

15. A system for time multiplex transmission of information between vehicle components, said system including a first and a second synchronizing units and a plurality of substantially similar transmission units connected to a bus having at least three bus conductors for power supply and transmission of signals between the units;

said synchronizing units each including means for detecting signals from a transmission unit on a first of the bus conductors, means for generating timing signals and means for detecting timing signals on a second of the bus conductors;

said first synchronizing unit including means for enabling it to assume an active mode of operation in which it regularly sends timing signals on the second bus conductor in the bus for synchronizing the transmission units, and for defining a plurality of time slots on the bus, said first synchronizing unit including means for enabling it to assume a standby mode of operation in which it does not send timing signals on the bus, the first synchronizing unit further including means for changing from its standby mode of operation to its active mode when signals from a transmission unit have been present on the first bus conductor for a comparatively short time, simultaneously as timing signals have not been present on the second bus conductor;

said second synchronizing unit including means for enabling it to assume an active mode of operation in which it regularly sends timing signals on the second bus conductor, the second synchronizing unit further including means for enabling it to assume a standby mode of operation in which it does not send timing signals on the bus, the second synchronizing unit further including means for changing from its standby mode of operation to its active mode not until signals from a transmission unit have been present on the first bus conductor a comparatively long time, simultaneously as timing signals have not been present on the second bus conductor;

said transmission units each having at least one of an input for receiving from a vehicle component information which shall be transmitted on the first bus conductor and an output for information transmitted on the first bus conductor, said transmission units each including means for detecting said timing signals on the second bus conductor, said transmission units each comprising means for enabling them to assume an active mode of operation in which a given transmission unit receives timing signals from one of said synchronizing units and selectively transfers in a predetermined time slot between a vehicle component and the first bus conductor information signals in correspondence to information on said one of an input and output, said transmission units each including means for enabling them to assume a standby mode of operation in which a given transmission unit does not selectively transfer information in correspondence to any information signals in any given time slot on the first bus conductor, to any said transmission units each having a mode change input for individual control of the conditions under which the transmission unit shall change from its standby mode of operation to its active mode;

a first group of said transmission units being controlled via their mode change inputs to go from their standby mode of operation to their active mode on the presence of the timing signals on the bus; and

a second group of said transmission units being controlled via their mode change inputs to change from their standby mode of operation to their active mode on the presence of information signals in at least one predetermined time slot on the first bus conductor, said second group being controlled via their mode change inputs to change from their active mode to their standby mode of operation in the absence of information signals in at least one predetermined time slot on the first bus conductor (BC1).

16. A system as claimed in claim 15, wherein each transmission unit includes means for sending one of a group consisting of a single analogue sampled potential and a single binary signal per time slot on the first bus conductor, and in that each transmission unit includes means for receiving one of a group consisting of a single analogue sampled potential and a single binary signal per time slot on the first bus conductor.

17. A system as claimed in claim 15, wherein each transmission unit includes means for enabling it to transfer information in at least three and at most five time slots in succession on the first bus conductor, and in that each transmission unit includes means for selecting its time slots independent of the time slots selected by the remaining transmission units.

18. A system as claimed in claim 15, wherein each transmission unit includes means controllable to transfer information in a first direction between a vehicle component and the first bus conductor solely during the first half of at least one time slot and to transfer information in a second direction between said vehicle component and the first bus conductor solely during the second half of said at least one time slot.