JPH0217814B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field> The present invention relates to a testing device for testing the hardware, particularly the input circuit, of a microcomputer for controlling an automobile engine.

<Prior art> When manufacturing and shipping a control unit with a built-in microcomputer that electronically controls fuel injection amount, ignition timing, etc. according to the operating status of an automobile engine, the hardware is inspected; Inputs corresponding to various virtual operating states were applied to the machine, and the control output at that time was compared with standard values to determine whether it was "OK" or "NG."

However, due to the engine incorporating the control unit (microcomputer) or due to changes in characteristics, the software (control program and data) may differ even though the hardware is the same.
The control output is not constant for the same input, and it is necessary to perform standard calculations for judgment due to differences in software specifications.
Since we had to calculate the specifications for more than one item, it took time to confirm the arrangements.

In addition, since the input and output circuits are checked by comparing control outputs calculated under various input conditions with standard values, it is difficult to determine which circuit is defective even if the output standard is "NG". It was difficult.

<Purpose of the Invention> In view of these conventional problems, the present invention enables rapid inspection response to changes in software specifications when inspecting microcomputer hardware, particularly input circuits, and eliminates defective input lines. The purpose is to enable instant judgment and easy correction.

<Configuration of the Invention> Therefore, as shown in FIG. 1, the present invention causes the engine control microcomputer to be inspected to operate under specific input conditions and output various input data as is from a predetermined output terminal. The inspection machine is equipped with a hard check operating means, and an input data providing means for providing various input data including specific input conditions to the microcomputer, and reading output data from a predetermined output terminal of the microcomputer. The present invention comprises an output data reading means and a comparing and determining means for comparing and determining the identity of input data and output data, and constitutes a testing device for microcomputer hardware, particularly input circuits.

<Example> Examples will be described below.

In Figure 2, 1 is a microcomputer for engine control, with CPU 2, RAM 3, and a mask.
ROM (M-ROM) 4, programmable ROM (P
-ROM) 5 and I/O interface 6, etc. Note that the control program is stored in the M-ROM 4, and table data and the like are stored in the P-ROM 5.

When mounted on a vehicle, the I/O interface 6
The input side is connected to the crank angle sensor, intake air flow meter, water temperature sensor, and various switches, etc., and the output side is connected to the fuel injection valve, ignition coil, etc., and the control program By operating the CPU 2 in accordance with the above, calculations are performed based on input data such as the rotation speed N, and the operation of the output side equipment is controlled by the control output.

Here, a hardware check program is stored in the M-ROM 4 together with the control program.

The hard check program uses NMI for non-maskable interrupt requests while the control program is running.
(Non-maskable interrupt) signal is generated, and various input data are set in advance under specific input conditions (for example, a combination of rotation speed N and start switch, such as when rotation speed N is 9000 rpm or more and the start switch is on, etc.) , conditions that are generally impossible)
It operates only when the following conditions are met, and stops due to one input condition. That is, as shown in the flowchart of FIG. 3, it is activated by the NMI signal and specific input conditions, and various data (N, N,
Q, Tw, ...) are all read from RAM3,
In step 2, these data are serially output to a predetermined output terminal L (an output terminal not used in a normal control program, for example, an output terminal to a light emitting diode for displaying self-diagnosis results). In this case, it is preferable to use two output terminals and output the data type signal from one of them. Note that the control program is also executed while this hard check program is being executed.

On the other hand, the inspection machine 7 is provided with an input data providing section 8 connected to the input terminal of the microcomputer 1 to be inspected, an output data reading section 9 and a comparison/judgment section 10 connected to the output terminal. According to the chart (operation program),
Perform inspection.

That is, in step 1 of FIG. 4, various input data (N,
Q, Tw, . . .) are given to the microcomputer 1 to be tested, and in step 2, an NMI signal is given. Of course, the power is turned on to the microcomputer 1 and the control program is running before this, and when specific input conditions and NMI signals are given, the hard check program also starts running, Input data is serially output as is from a predetermined output terminal.

Next, in step 3, the output data output from the predetermined output terminal is read, and in step 4, each output data is compared with the predetermined upper and lower limits in correspondence with each input data, and the output data is determined to be within the same range. It is determined whether or not. Of course, this determination is made for each data. If it is within the range, proceed to step 5 and display "OK"; if outside the range, proceed to step 6 and display "NG". This display is also performed for each data, that is, for each input line, so “NG”
You can know which input line has a problem.

In this case, if the hardware of microcomputer 1 is the same, even if the software specifications change,
As long as it has a hard check program,
Regarding testing of input circuits, the standards on the testing machine side may be the same.

In addition, the output circuit inspection will remain as it is, but when changing the software specifications, the standard calculation for input circuit inspection will no longer be necessary, so the total number of standard calculation items will be around 15, and the design man-hour will be reduced. can be drastically reduced.

Further, by stopping the control program during the test and providing the hard check program with a function to output data from all output terminals, it is possible to test the output circuit at the same time.

<Effects of the Invention> As explained above, according to the present invention, when testing the hardware of a microcomputer, especially the input circuit, if the hardware is the same, the standards on the testing machine side can be the same, and changes in software specifications are not required. On the other hand, it is possible to quickly respond to inspections, and since defective input lines can be immediately determined, corrections can be made easily.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the configuration of the present invention, Figure 2 is a block diagram showing the configuration of the present invention.
The figure is a schematic diagram of an inspection device showing an embodiment of the present invention.
FIG. 3 is a flowchart of a hard check program provided in the microcomputer to be inspected, and FIG. 4 is a flowchart of a program for operating the inspection machine. 1...Microcomputer, 7...Inspection machine,
8... Input data providing section, 9... Output data reading section, 10... Comparison/judgment section.

Claims (1)

[Claims] 1. The engine control microcomputer to be inspected is equipped with a hard check operating means that operates under specific input conditions and outputs various input data as is from a predetermined output terminal, while the inspection machine is equipped with An input data providing means for providing various input data including specific input conditions, an output data reading means for reading output data from a predetermined output terminal of the microcomputer, and a comparison judgment for identity between the input data and the output data. 1. A hardware inspection device for a microcomputer, characterized in that it is equipped with a comparison/judgment means.