Slave bus controller circuit for class A motor vehicle data communications

• US 5,418,526 A
• Filed: 07/18/1994
• Issued: 05/23/1995
• Est. Priority Date: 05/04/1992
• Status: Expired due to Fees

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Ford Motor Company
• Inventors: Crawford, Robert D.
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US08/276,150
• Time in Patent Office: 309 Days
• Field of Search: 340/825.06, 340/825.5, 370/85.1, 370/85.2, 370/85.11, 370/85.12, 370/85.13, 370/85.14, 370/85.15, 370/85.3
• US Class Current: 370/464
• CPC Class Codes: H04L 12/40013 Details regarding a bus controller
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling
• CPC Class Codes: H04L 2012/40273 the transportation system being a vehicle
• CPC Class Codes: H04L 7/0331 with a digital phase-locked loop [PLL] processing binary samples, e.g. add/subtract logic for correction of receiver clock H04L7/0337 takes precedence
• CPC Class Codes: H04L 7/044 using a single bit, e.g. start stop bit

Abstract

A Class A node comprising a slave bus controller circuit (SBCC) operates as a remote input/output device for performing Class A communications for a master Class B node over an interconnecting SAE J1850 or similar network. The SBCC receives messages from one or more Class B nodes to receive output data which appears at one or more output ports of the SBCC. Output data may be directly provided or may be combined with mask data such that only mask selected bits of the output data are passed to the one or more output ports of the SBCC. Input data directly connected to one or more input ports of the SBCC are transmitted back to a master node as an in-message response of the network. The SBCC provides inexpensive Class A communications using the SAE J1850 protocol which is primarily intended for Class B communications. The SBCC is inexpensive because of its simplified circuitry, its ability to operate without a controlling processor and, in some embodiments, the implementation of its master clock as a RC oscillator which does not directly determine bit timing for the SBCC but is used to measure the bit timing of the master node from which it is receiving messages.

Claims

1. A remote input/output signal slave circuit for a master control circuit operable on a multiplex network for a motor vehicle, said slave circuit being positioned at a remote location relative to said master control circuit for controlling and monitoring operations at said remorse location in response to control messages from said master control circuit and comprising:

receiver means connected to said network for receiving said control messages from said master control circuit;

clock means for generating clock signals for operating slave circuit;

message decoder means connected to said receiver means for decoding said control messages;

output register means for receiving output data contained within said control messages from said message decoder means, said output data comprising a plurality of output data bit positions and being used for controlling operations at said remote location, said output register means comprising mask register means connected to said message decoder means, said control messages including mask data identifying output data bit positions to be modified by said output data contained within said control messages such that said slave circuit can be controlled by two or more master control circuits with mask data transmitted by each master control circuit ensuring independent control of output data corresponding to each of said two or more master control circuits;

input register means for receiving input data to be transmitted to said master control circuit via said network;

data encoder means connected to said input register means for encoding said input data for transmission onto said network; and

transmitter means connected between said data encoder means and said network for transmitting encoded input data for said master control circuit onto said network as an in-message response of said control master such that said input data is transmitted to said master control circuit without said slave circuit having to gain control over said network.

2. A remote input/output signal slave circuit for a master control circuit operable on a multiplex network for a motor vehicle, said slave circuit being positioned at a remote location relative to said master control circuit for controlling and monitoring operations at said remote location in response to control messages from said master control circuit and comprising:

receiver means connected to said network for receiving said control messages from said master control circuit;

clock means for generating clock signals for operating said slave circuit, said clock means comprising a local oscillator and a bit timer circuit for synchronizing and calibrating said local oscillator to timing defined by said control message received from said master control circuit, said bit timer circuit comprising a counter circuit, a logic circuit which clears and enables said counter circuit to count pulses which are a multiple of a network clock during a start of message signal received by said slave circuit, a divider circuit for dividing resulting counts by a defined clock divisor to generate synchronized bit clock signals for said slave circuit;

message decoder means connected to said receiver means for decoding said control messages;

output register means for receiving output data contained within said control messages from said message decoder means, said output data comprising a plurality of output data bit positions and being used for controlling operations at said remote location;

input register means for receiving input data to be transmitted to said master control circuit via said network;

data encoder means connected to said input register means for encoding said input data for transmission onto said network; and

transmitter means connected between said data encoder means and said network for transmitting encoded input data for said master control circuit onto said network as an in-message response of said control message such that said input data is transmitted to said master control circuit without said slave circuit having to gain control over said network.

3. A remote input/output signal slave circuit as claimed in claim 2 further comprising sleep timer means for disabling said local oscillator after a defined idle network time period and restarting said local oscillator upon network activity.

4. A remote input/output signal slave circuit as claimed in claim 3 wherein said local oscillator is an RC oscillator.

5. A remote input/output signal slave circuit for a master control circuit operable on a multiplex network for a motor vehicle, said slave circuit being positioned at a remote location relative to said master control circuit for controlling and monitoring operations at said remote location in response to control messages from said master control circuit and comprising

receiver means connected to said network for receiving said control messages from said master control circuit;

clock means for generating clock signals for operating said slave circuit;

message decoder means connected to said receiver means for decoding said control message;

output register means for receiving output data contained within said control message from said message decoder means, said output data comprising a plurality of output data bit positions and being used for controlling operations at said remote location;

input register means for receiving input data to be transmitted to said master control circuit via said network;

data encoder means connected to said input register means for encoding said input data for transmission onto said network;

transmitter means connected between said data encoder means and said network for transmitting encoded input data for said master control circuit onto said network as an in-message response of said control message such that said input data is transmitted to said master control circuit without said slave circuit having to gain control over said network; and

input control means for latching input signals into said input register means during generation and transmission of said in-message response of said control message such that invalid asynchronous input signal changes are prevented, said input control means latching said input signals a defined time after receipt of output data in said output register means such that status information resulting from said output data and output data receipt confirmation is returned in said in-message response of said control message.

6. A method of interfacing equipment to be controlled and monitored by two or more master control circuits via a multiplex wiring network in a motor vehicle, said method comprising the steps of:

receiving control messages from said two or more master control circuits via said network, said messages each including output data for devices to be controlled and mask data identifying output data bit positions to be modified by said output data contained within said control message;

decoding said control message;

loading said output data into an output register;

loading said mask data into a mask register associated with said output register;

outputing said output data to output data bit positions identified by said mask data;

receiving input data to be transmitted to said master control circuit via said network;

encoding said input data for transmission to said master control circuit via said network; and

transmitting encoded input data to said master control circuit via said network as an in-message response of said control message.

7. A method of interfacing equipment to be controlled and monitored by two or more master control circuits via a multiplex wiring network in a motor vehicle as claimed in claim 6 further comprising the steps of:

synchronizing and calibrating a local oscillator of said equipment to timing defined by said control messages received from said two or more master control circuits;

clearing a counter circuit;

enabling said counter circuit to count pulses which are a multiple of a network clock during start of message signals contained within said control messages;

dividing counts accumulated in said counter circuit during said start of message signals by a defined clock divisor to generate synchronized and calibrated clock signals for said equipment.

8. A remote input/output signal slave circuit for a master control circuit operable on a multiplex network for a motor vehicle, said slave circuit being positioned at a remote location relative to said master control circuit for controlling and monitoring operations at said remote location in response to control messages from said master control circuit and comprising:

receiver means connected to said network for receiving said control messages from said master control circuit;

clock means for generating clock signals for operating said slave circuit;

message decoder means connected to said receiver means for decoding said control message;

output register means for receiving output data contained within said control message from said message decoder means, said output data comprising a plurality of output data bit positions and being used for controlling operations at said remote location;

input register means for receiving input data to be transmitted to said master control circuit via said network;

data encoder means connected to said input register means for encoding said input data for transmission onto said network;

transmitter means connected between said data encoder means and said network for transmitting encoded input data for said master control circuit onto said network as an in-message response of said control message such that said input data is transmitted to said master control circuit without said slave circuit having to gain control over said network; and

input control means for latching input signals into said input register means during generation and transmission of said in-message response of said control message such that invalid asynchronous input signal changes are prevented, said input control means latching said input signals a defined time after receipt of output data in said output register means and further comprising a looping circuit connected between said output register means and said input register means for looping at least one of said output data bit positions from said output register means to said input register means such that status information resulting from said output data and output data receipt confirmation is returned in said in-message response of said control message.

9. A remote input/output signal slave circuit as claimed in claim 8 wherein said looping circuit comprises a flip-flop circuit.

10. A method of interfacing equipment to be controlled and monitored by a master control circuit via a multiplex wiring network in a motor vehicle, said method comprising the steps of:

receiving a control message for said master control circuit via said network, said message including output data for devices to be controlled;

decoding said control message;

loading said output data into output register means;

receiving input data to be transmitted to said master control circuit via said network;

encoding said input data for transmission to said master control circuit via said network;

transmitting encoded input data to said master control circuit via said network as an in-message response of said control message; and

looping at least one of said output data from said output register means to be received as input data to be transmitted to said master control circuit via said network such that status information resulting from said output data and output data receipt confirmation is returned in said in-message response of said control message.

11. A method of interfacing equipment to be controlled and monitored by a master control circuit via a multiplex wiring network in a motor vehicle as claimed in claim 10 wherein said step of looping at least one of said output data from said output register means to be received as input data to be transmitted to said master control circuit via said network comprises the step of connecting a flip-flop circuit between said output register means and input register means which receives said input data.