Patent Publication Number: US-6662087-B1

Title: Backward compatible diagnostic tool

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a diagnostic tool for use in connection with diagnosing vehicle systems and particularly a diagnostic tool which accommodates different format storage mediums. 
     For many years, electrical testers have been provided for connection to a vehicle&#39;s computer system through a test port which is a connector allowing the test equipment to interrogate and diagnose vehicle systems for maintenance and servicing. Such systems include, for example, an engine mounted control module, a heating ventilation and air conditioning module (HVAC), an instrument panel cluster and the like. Different vehicle manufacturer&#39;s utilize different communication protocols and as vehicle models change, each vehicle has its own signal parameters representative of normal or abnormal conditions within the vehicle. Thus, with the thousands of vehicles now including test ports, several using different communication protocols and each with their own signals, it is necessary to provide stored data for controlling testers employed for the servicing of vehicles which store the test data for each vehicle model and year as well as provide a communication protocol which allows the tester to communicate with a given vehicle under service. 
     Several hundred thousand testers have, in the past, employed an 8-bit microprocessor, such as a Motorola 6803, as the microprocessor for processing data. Each tester can employ numerous memory cartridges which include stored data and control information for the vehicles. As can be appreciated, with the hundreds of thousands of testers in the market and the numerous cartridges for each tester and as additional vehicles are included, replacing the somewhat outdated 8-bit microprocessor with a new system would require reprogramming of the data contained by all of the existing cartridges for use with the 8-bit microprocessor as well as obsoleting the service cartridges now available to the service technicians. As vehicles become older, their cartridges gradually become obsolete and to program a new microprocessor system with all such information would consume memory that is better used for current and new vehicles with which a tester is to be employed. 
     As a result, it is desirable to provide an improved tester with faster processing capabilities, improved memory and yet one which will allow the use of existent cartridges for older vehicles using the earlier microprocessor platform. 
     SUMMARY OF THE INVENTION 
     The system of the present invention accommodates this need by providing a cartridge adapter for receiving existing vehicle diagnostic cartridges programmed for use with an 8-bit microprocessor. The adapter receives existing cartridges and is coupled to a field programmable gate array (FPGA) programmed to emulate the operation of the 8-bit microprocessor, such as a Motorola 6803, and supplies information to a 32-bit microprocessor coupled to a display and control panel to emulate the operation of a system for which the cartridges have been programmed. Additionally, the 32-bit microprocessor includes programming for new vehicles as well as the ability to use updated vehicle information through flash memory to be continuously updated. A second FPGA provides a communication interface between the vehicle input/output circuit for providing communication using the various protocols employed by different vehicle manufacturers. 
     With such a system, therefore, existent cartridges for earlier vehicles can be employed and testing conducted by field technicians in the same manner as they have been accustomed to while using a tester which is programmed for use with newer vehicles such that service personnel can service all vehicles utilizing familiar testing techniques for earlier vehicles as well as a higher speed, more efficient microprocessor for both older vehicles and new vehicles. 
     These and other features, objects and advantages of the present invention will become apparent upon reading the following description thereof together with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front elevational view of a test instrument embodying the present invention; 
     FIG. 2 is a block and schematic electrical circuit diagram of the tester shown in FIG. 1; and 
     FIG. 3 is a flow diagram of the software employed to read and control data from a plug-in cartridge. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring initially to FIG. 1, there is shown a test instrument  10  embodying the present invention and which has a relatively compact housing  12  with an enlarged upper section for accommodating a 320 by 240 pixel liquid crystal display (LCD)  14 . Display  14  emulates not only the 4 by 20 pixel display of the earlier test instruments sold by the assignee of the present invention as a Monitor 4000 instrument but also emulates the keypad of the Monitor 4000 instrument for allowing the operator to utilize instrument  10 , as described below, in the same manner as the earlier test instrument was employed. Thus, use of instrument  10  by field service personnel draws upon the familiarity of the service personnel with the earlier test instrument and employs the existing cartridges storing vehicle data information for existing vehicles. As used herein the term “data” also includes vehicle system information from the vehicle and communication to the vehicle (e.g., codes, messages, commands, instructions and requests). In addition, the term “language”, as used herein, includes instructions, codes or sets. 
     Housing  12  is ergonomically designed to be easily hand-held and includes a keypad  16  for the entry of displayed data once selected by utilization of cursor keys  17 ,  17 ′,  18  and  18 ′ and the actuation of an entry switch  19 . Housing  12  includes a socket  22  on the back side of the instrument for receiving memory cartridges  24  for controlling the instrument to communicate with vehicles under test. Cartridges  24  are the same cartridges as exist for use in connection with the Monitor 4000 system and typically will include data for a given vehicle make and series of such vehicle models for a period of time, such as four to six years as only one example. In addition, the test instrument  10  includes a flash memory socket  25  for receiving updated data for new vehicles stored in a flash memory chip. A socket  26  receives a connector  28  coupled to a wire harness  30  which, in turn, includes a plug on the opposite end (not shown) selected for a given vehicle for plugging into the vehicle&#39;s test socket to interface the test instrument  10  with the vehicle&#39;s computer. Wire harness  30  may also include a power plug allowing an instrument to be plugged into the vehicle&#39;s electrical system through a conventional cigarette lighter plug. 
     The heart of the test instrument, as seen with reference to FIG. 2, is a 32-bit microprocessor  30  comprising, in the preferred embodiment, an integrated microprocessor and peripheral circuit on a single chip which includes a universal serial bus (USB) interface, a video display controller, and a LCD controller. In the preferred embodiment, a Motorola MPC 823 microprocessor is employed and is coupled to the display  14  through bus  15 . The microprocessor receives input command control signals from keypad  16  through interface bus  13  and is coupled to a pair of field programmable gate arrays (FPGAs)  40  and  50  through data address lines  45  and  55 , respectively. FPGA  40  and FPGA  50  in the preferred embodiment are model 10K50E circuits made by Altera, although other FPGAs or other programmable circuits can be employed. For example, FPGAs  40  and  50  can be replaced with application specific integrated circuits (ASICs). 
     FPGAs  40  and  50  are coupled to one another by a 16-bit parallel communication link  42 . FPGA  40  is programmed to communicate with the vehicle input/output interface circuit  60  such that for any given vehicle, such as, for example, Chrysler, Ford or General Motors, the data protocol allows communication between the test instrument  10  and the vehicle under test. FPGA  50  is also coupled to a hip connector socket  64  through bus  62  for receiving control information from a cartridge  24 , which is coupled to FPGA  50  through a cartridge adapter circuit  70 . Circuit  70  includes an eight data line adapter, a serial universal asynchronous receiver transmitter (UART) and memory allowing the FPGA  50  to read data from the cartridge  24 , which is plugged into a cartridge port  22  in adapter  70 , which has a hip plug  74  which is connected to hip connector  64  for interconnecting the adapter to the test instrument  10  and the cartridge  24  to adapter  70 . Thus, cartridge  24  is coupled to microprocessor  30  through FPGA  50 . FPGA  50  is programmed to emulate the earlier 6803 microprocessor for which the existent cartridges  24  are programmed. FPGAs  40  and  50  can be conventionally programmed to emulate the 6803 microprocessor core as well as the protocols for use with different vehicles. One of skill in the art will appreciate that the present invention could utilize a microprocessor, other than a 32-bit microprocessor (e.g., a 64-bit microprocessor), in combination with an emulated legacy microprocessor (e.g., 8-bit or 16-bit microprocessor). 
     When instrument  10  is employed with existing cartridges, the FPGAs  40 ,  50  are programmed as indicated by block  100  in FIG. 3, as noted above, with the emulation templates for the 6803 microprocessor as well as the vehicle input/output protocols employed with the different vehicles. When the service technician powers up the test instrument, a main menu on display  14  prompts the technician to select “Monitor 4000 emulation” and, if a vehicle being serviced is covered by an existent program cartridge, the technician selects this operation by highlighting the selection using cursors  17 ,  17 ′,  18 , and  18 ′ and actuating an entry command via switch  19 . When the test instrument is connected to the vehicle and the proper cartridge  24 , the instrument reads vehicle data from the FPGA  50  buffer, as indicated by block  110 , to initially decode the data header, as indicated by block  112 , and determines in block  114  whether it was input/output (I/O) data. If it is I/O data, the data is written to FPGA  50 , as indicated by block  116 , and processed according to the existent coding information on cartridge  24 . As the vehicle data is received and processed, it will provide the vehicle operator with output display data and, as the program loops through the path including line  115 , the vehicle data will become display data which is tested at block  118  and, if it is, it will be sent via bus  15  to LCD  14  as indicated by block  120 . If the data was neither I/O data nor display data, it is further tested as indicated in block  122  to determine whether it is input data from keypad  16 . If it was, the key stroke information is decoded and applied to the buffer of FPGA  50  as indicated by block  124  which responds to the data to provide a control signal to the system for responding to the operator-entered signal. 
     FPGA  50  is programmed to provide a display  80  (FIG. 1) on the LCD  14  which emulates the previous Monitor 4000 test instrument. Thus, LCD  14  provides a 4 by 20 pixel display panel  82  corresponding to the LCD of a Monitor 4000 instrument. Below the emulated LCD  82  is an emulated keypad  84  including numeric keypads and an enter switch which can be highlighted by the operator by actuating cursor controls  17 ,  18  and  17 ′,  18 ′. Once the key switch desired is highlighted, the enter switch  19  is actuated by the operator to enter the command indicated by the emulated Monitor 4000 display  80 . Thus, instrument  10  allows operation which mimics exactly the operation of an existing test instrument utilizing existing cartridges  24  in addition to its independent operation, without the use of a cartridge  24 , for newer vehicles through the direct programming of microprocessor  30 . By providing an emulation of the earlier microprocessor, the ability to use thousands of existing cartridges  24  with memory for controlling the instrument can be employed and familiar testing techniques employed by the service personnel utilizing an updated instrument which can recognize not only existing program cartridges but also diagnostic programs for newer vehicles as well as receive additional programming information through the use of a faster 32-bit microprocessor. 
     It will become apparent to those skilled in the art that various modifications to the preferred embodiment of the invention as described herein can be made without departing from the spirit or scope of the invention as defined by the appended claims.