Device for the bus-networked operation of an electronic unit with microcontroller, and its use

• US 5,892,893 A
• Filed: 03/26/1997
• Issued: 04/06/1999
• Est. Priority Date: 03/26/1996
• Status: Expired due to Term

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: Mercedes-Benz Bank AG (Mercedes-Benz Group AG)
• Inventors: Hanf, Peter, Minuth, Jurgen, Setzer, Jurgen
• Primary Examiner(s): Coleman, Eric
• Assistant Examiner(s): MONESTIME, MACKLY
• Application Number:
  US08/825,027
• Time in Patent Office: 741 Days
• Field of Search: 395/182.01, 395/182.02, 395/185.09, 395/182.07, 395/182.2
• US Class Current: 714/3
• CPC Class Codes: G06F 1/3209 Monitoring remote activity, e.g. over telephone lines or network connections
• CPC Class Codes: G06F 13/4072 Drivers or receivers G06F13/4086 takes precedence; for multistate logic circuits H03K19/0002
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A device for bus-networked operation of an electronic unit having microcontroller has a semiconductor circuit which is supplied from a superordinate potential, and is connected between a bus protocol module of the microcontroller and the cores of a two core bus. The semiconductor circuit, which has at least two operating modes, "transmission and reception" (NORMAL) and "sleep" (SLEEP), compromises: a receiving circuit connected to the two bus cores, whose output communicates with a reception input of the bus protocol; a transmitting circuit coupled to receive the transmission output of the bus protocol function; a wake-up identification circuit connected to the cores of the two core bus, and having a wake-up input and switching means for providing, at a control output, a switch-on signal after identification of a wake-up signal from the wake-up input or from the bus, and for emitting a switch-off signal in the SLEEP mode. A voltage regulator, supplied from superordinate potential, provides a regulated output voltage to the microcontroller and to the bus protocol module. The voltage regulator has a control input which communicates with the control output of the semiconductor circuit, and is configured to switch on in the presence of the switch-on signal and to switch off in the presence of the switch-off signal,

Claims

1. Device for the bus-networked operation of an electronic unit having a microcontroller for implementing communications with other units via a two-core bus, said device comprising:

a bus protocol module in said microcontroller, for controlling communications with said other units, said bus protocol module having at least two operating modes as a function of status signals of the microcontroller, said operating modes comprising at least a transmission and reception mode NORMAL, and a sleep mode SLEEP;

a semiconductor circuit arranged in a signal flow path between said bus protocol module and said two core bus, and supplied from a superordinate potential, said semiconductor circuit comprising

a receiving circuit connected to cores of the two core bus and having an output coupled to communicate with a receiving input of the bus protocol module;

a transmitting circuit connected to said cores of the two core bus and having a transmitting output stage, the input of which is coupled to communicate with a transmission output of the bus protocol module; and

a wake-up identification circuit connected to said cores of said two core bus and having a wake-up input and switching means for providing, at a control output, a switch-on signal after identification of a wake-up signal received at said wake-up input or from the two core bus, and for emitting a switch-off signal in the operating mode "sleep"; and

a voltage regulator coupled to be supplied from the superordinate potential, and providing a regulated output voltage to the microcontroller and to the bus protocol module, said voltage regulator having a control input which communicates with the control output of the semiconductor circuit, and being configured to switch on in the presence of the switch-on signal and to switch off in the presence of the switch-off signal.

2. Device according to claim 1 wherein the voltage regulator has a reset output and an autonomous circuit which generate a reset signal at said reset output after the voltage regulator has been switched on for the purpose of providing a secondary potential for the supply of the microcontroller, which reset signal is input to a reset input of the microcontroller.

3. Device according to claim 1 wherein the semiconductor circuit comprises means, operative upon occurrence of a bus error that impairs normal communication via the two bus cores, for reconfiguring said semiconductor circuit to utilize a best possibility which still exists for emergency communication via the bus, both with regard to its receiving circuit and with regard to its transmitting circuit, independently of the microcontroller.

4. Device according to claim 1 further comprising two termination elements connected to the semiconductor circuit, and having operating parameters which are defined as a function of the number of bus subscribers, wherein the semiconductor circuit further comprises:

a bus fault identification circuit for identifying faults in said bus;

a cooperative bus termination changeover circuit for influencing the bus termination; and

a bus fault and wake-up evaluation circuit for conditioning and outputting at least one error or interrupt signal to the microcontroller.

5. Device according to claim 1 wherein the voltage regulator has means for generating a switch-on-responsive reset signal, and an output for emitting said reset signal, which output is connected to the microcontroller.

6. Device according to claim 1 wherein the receiving circuit is configured to be adapted, independently of the transmitting means, for the best possibility which still exists for emergency communication via the bus.

7. Device according to claim 4 wherein the bus error identification circuit, and bus termination changeover circuit are configured to switch-connect the termination elements to the two bus cores of the two core bus in the NORMAL operating mode and, to switch-connect a first back-up termination element integrated in the semiconductor circuit to the two bus cores, instead of at least one of the said termination elements in the SLEEP mode, and, depending on the nature of an identified bus fault, to switch-connect second and third back-up terminations integrated in the semiconductor circuit to the two bus cores, instead of at least one of the termination elements, to at least one of the two bus cores.

8. Device according to claim 1 wherein the receiving means and transmitting means are intrinsically realized, whereby they are tolerant of all possible errors in an application-specific manner throughout the bus.

9. Device according to claim 1 wherein at least the transmitting output stage is disconnectable from the bus in the event of an inherent fault of the device.

10. Device according to claim 1 wherein the transmitting circuit comprises means for switching off the power supply of the transmitting output stage upon the occurrence of an inherent fault of the device.

11. Device according to claim 1 wherein the semiconductor circuit is configured so that, in the SLEEP mode, termination of the two bus cores is asymmetric (in terms of impedance) with respect to a reference potential.

12. Device according to claim 7 wherein a first back-up termination is connected to the superordinate potential.

13. Device according to claim 7 wherein the first back-up termination is a resistor having a value which is approximately a multiple of the value of the normal termination resistor, said multiple corresponding to a number of bus subscribers.

14. Device according to claim 7 wherein the second and third back-up terminations are impressed current sources.

15. Device according to claim 7 wherein the second and third back-up terminations are high-value resistors.

16. Device according to claim 1 wherein the semiconductor circuit has the further operating modes RECEIVE ONLY and STANDBY, in which either the power supply of the transmitting output stage can be switched off or the transmitting output stage can be selectively disconnected from the bus.

17. Device according to claim 1 wherein the semiconductor circuit comprises a circuit for monitoring at least the superordinate potential UBATT/VBATT to detect drops below a first limit value, as well as a first evaluation circuit which evaluates an identified drop below the first limit value as a POWER FAIL error or interrupt signal for the microcontroller.

18. Device according to claim 1 wherein the semiconductor circuit comprises a circuit for monitoring the supply potential of the microcontroller to detect drops below a second limit value, as well as a second evaluation circuit which evaluates an identified drop below the second limit value as a POWER FAIL error or interrupt signal for the microcontroller.

19. Device according to claim 17 further comprising a bus error identification circuit, a bus termination changeover circuit, and a bus fault evaluation circuit for conditioning at least one error or interrupt signal for output to the microcontroller;

wherein an output of said bus fault evaluation circuit is logically combined with an output of said first evaluation circuit.

20. Device according to claim 17 further comprising a logic element which causes the error or interrupt signal to be generated when both limit values have been exceeded in a downward direction.

21. Device according to claim 18 further comprising a logic element which causes the error or interrupt signal to be generated when both limit values have been exceeded in a downward direction.

22. Device according to claim 1 wherein the transmitting output stage is disconnected from the bus when the superordinate potential drops below a predetermined limit value.

23. Device according to claim 22 wherein disconnection is effected by blocking a control input for active connection of the transmitting circuit to the bus.

24. Device according to claim 3 wherein upon the occurrence of a fault, the identification of a best possibility which still exists for emergency communication via the bus and the setting, reconfiguration or adaptation of the semiconductor circuit are effected by analog comparison of bus core potentials with tolerance windows.

25. Device according to claim 23 wherein the setting, reconfiguration or adaptation are effected in a manner which avoids message losses.

26. Device according to claim 1 wherein the semiconductor circuit comprises filter elements arranged at least between each of the two bus cores and a corresponding input of the receiving circuit, and between the wake-up input and the wake-up identification circuit.

27. Device according to claim 1 wherein the semiconductor circuit is monolithically realized on a semiconductor chip.

28. Device according to claim 1 wherein the semiconductor circuit is monolithically integrated with the bus protocol module.

29. Device according to claim 1 wherein the semiconductor circuit is monolithically integrated with the microcontroller.