Method and apparatus for testing automotive control units

• US 5,490,065 A
• Filed: 05/02/1994
• Issued: 02/06/1996
• Est. Priority Date: 06/29/1991
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Horbelt, Michael, Pruellage, Arno, Hoenninger, Harald, Seitel, Hans
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): Walder, Jr., Stephen J.
• Application Number:
  US08/234,677
• Time in Patent Office: 645 Days
• Field of Search: 364/424.04, 364/442, 364/151, 364/424.03, 73/114, 73/113
• US Class Current: 701/29
• CPC Class Codes: G01R 31/282 Testing of electronic circuits specially adapted for particular applications not provided for elsewhere G01R31/2801 and G01R31/2851 take precedence

Abstract

A method and a device for testing control units are presented, serving the purpose of operation and quality testing of automotive control units. The method comprises event control of individual test steps with defined signals from and to the test unit, thus reducing the test time. The method, furthermore, encompasses a test with square wave signals applied to the control unit, which are recognized by the control unit and read out to the test unit, thus increasing the depth of the test.

Claims

1. Method of testing a control unit (10), for control of an internal combustion engine, using an operational program and a test program,

wherein the test program, in which adjustable simulated measurement values are applied to at least one of inputs and outputs of the control unit to test said unit, and resulting signals output by the control unit are then transferred to an external test system (7) where they are checked for validity, comprises the steps of:

(i) applying (14,

     16) said simulated measurement values to said control unit (10);

(ii) confirming, to the control unit (10), the validity of the applied measurement values by generating an edge signal (20) only at a predetermined input line (18) of the control unit (10);

(iii) processing (70-78) said applied measurement values in said control unit (10), and storing results of said processing in a memory (9);

(iv) confirming, to said external test system (7), completion of said processing in said control unit, by generating a further edge signal only at a predetermined output line (17) of said control unit (10); and

,

(v) following completion of said processing, transmitting results of said processing via a serial bus (19) to said external test system, which test system (7) checks said results for correctness; and

wherein the operational program, which is used during normal operation of the control unit, comprises the steps of;

(i) detecting operating parameters with the predetermined input line; and

(ii) outputting control signals with the predetermined output line.

2. Method according to claim 1, wherein

the process results stored in memory (9) are transferred to the test system at the end of the test.

3. Method according to claim 1, wherein

the measurement data in the control unit (10) are processed by a test program stored in the control unit (10).

4. Method according to claim 1, wherein

the test program verifies the operation of the memory (9) of the control unit and stores the test results in the memory (9).

5. Method according to claim 1, wherein

the control unit is initialized (67) at the beginning of the test;

the test program stores certain data in a free area of the memory (9) of the control unit and/or in certain registers of the control unit, and wherein

during the process of the test, the test program verifies the contents of said memory area and/or register and wherein the program is terminated if the data in said memory area and/or register are found to be invalid.

6. Method of testing a combustion engine control unit (10) using an external testing unit (7), comprising the steps of:

carrying out said testing as a series of individual steps;

applying, during one of said individual steps, a regularly varying linear alternating signal (13) to at least one input line (14) of the control unit (10);

successively;

sampling said alternating signal by said control unit,

processing said sampled alternating signal by said control unit, and

immediately generating an output signal (15) by said control unit, having a level according to each sampling result on a preselected output line of said control unit; and

evaluating in said external testing unit (7) time behavior (91-96) of said output signal (15) in relation to said alternating signal (13,

     90) on said preselected input line (14).

7. Method according to claim 6, wherein

under control by a subprogram of the test program, the alternating signal, present at at least one input (14) of the control unit (10), and the read-out of the result are called up at certain times and processed by the control unit (10).

8. Test unit (7) for testing an automotive control unit (10), comprising:

a controllable simulation and measuring unit (11) for generating simulated measurement signals for application to said control unit (10) and for acquiring output signals from said control unit;

a serial data transmission interface (15, 16,

     17) for exchange of data to and from the control unit (10),

means in said test unit (7) for confirming to said control unit (10) the validity of said simulated measurement signals by generating a first edge signal (20) only at a predetermined output (18) of said test unit (7), with the predetermined input line (18) during normal operation of the control unit serving to detect operating parameters, and

means in said control unit (10) for confirming to said test unit (7) correct processing of the measurement data by generating a further edge signal (21) only at a predetermined output (17) of the control unit (10) which is connected to an input of the test unit (7), with the predetermined output line (17) during normal operation of the control unit serving to output control signals.

9. Test unit according to claim 8, wherein the data transfer between the control unit and the test computer takes place via serial bus interface (19).

10. Test unit according to claim 8, wherein

upon the appearance of said further edge signal, a next set of measurement data is applied, and is confirmed to be valid by a repeated generation of the first edge signal.

11. Test unit according to claim 10, wherein

a counter, which contains the number of measurement data read out, is incremented before read-out of the measurement data.

12. Test unit according to claim 11, wherein,

after a certain value is reached by the counter, the processed results are demanded from the control unit.

13. Test unit according to claim 11, wherein

a counter in the control unit is also incremented before processing of the applied measurement data, and wherein the count is stored in the memory (9) together with the corresponding processed results.

14. Test unit according to claim 13, wherein,

controlled by the test computer, at the end of the test, the process results, together with the corresponding counts, are transferred to the test computer and compared to the nominal or command values for each count.

15. Test unit according to claim 14,

wherein results of an operability test of said memory (9) of said control unit (10) are transmitted to said test computer, and evaluated in said test computer (8).