JPH05158724A - Inter-lsi connection diagnostic system - Google Patents

Abstract

PURPOSE:To specify a fault occurred between the specific LSIs before the use of an inter-LSI connection diagnostic system by checking each inter-LSI connection at start up of the system with plural LSIs mounted on a base board. CONSTITUTION:The LSI 10, 30 and 50 contain the diagnostic control circuits 11, 31 and 51 which output the data decided previously by these LSI 10, 30 and 50 to compare both data signals with each other for detection of the coincidence between both signals and also diagnose the connections secured among the LSI 10, 30 and 50. In such a constitution, the data outputted from the diagnostic control circuits of both LSIs are compared with each other when an inter-LSI connection diagnostic system is started. Thus the normal inter-LSI connection is diagnosed if both data are coincident with each other. If not, the occurrence of a fault is detected.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a plurality of LSIs on a substrate.
The present invention relates to a diagnostic method for diagnosing inter-LSI connection at system startup when an (integrated circuit) is mounted.

[0002]

2. Description of the Related Art Conventionally, in a device composed of a plurality of LSIs, when the power is turned on between the LSIs, the LSIs are in an initial setting state, but the LSIs are unconditionally connected except for a bus connection. Is common.

[0003]

By the way, the conventional method diagnoses the inside of the LSI, but presupposes that the interface with the outside operates normally or that it operates normally under a certain condition. However, if there is an abnormality in a place that is supposed to be normal, there is a stall, but if such a fault occurs due to the connection relationship with multiple LSIs, it is difficult to identify the fault location. ..

[0004]

In order to solve the above-mentioned problems, the present invention comprises the following means. That is, in a device composed of a plurality of LSIs, two data are compared inside each LSI to detect the coincidence of both signals and to be predetermined by each LSI in order to diagnose the connection between the LSIs. By providing a diagnostic control circuit having a function of outputting data, by comparing the data output from the diagnostic control circuit of one LSI with the data output from the diagnostic control circuit of the other LSI after the initial diagnosis is completed. If the data match, the connection between the LSIs is diagnosed as normal, and if the data does not match, the failure occurrence is detected.

[0005]

Therefore, when a plurality of LSIs are mounted on the board, the connection between the LSIs is checked when the system is started up, and the failure occurs between which LSI and which LSI before starting to use the system. Can be specified.

[0006]

The present invention will be described below with reference to the drawings. FIG. 1 shows an LSI connection model created for explaining an embodiment of the present invention. In this embodiment, three LSIs, that is, an LSI 10, an LSI 30, and an LSI 50 are mounted on a base.
A diagnostic method for the connection between the LSIs will be described below. Here, the LSI 10 is provided with a diagnosis control circuit 11 for controlling diagnosis by a diagnosis mode signal, and the LSIs 30 and 50 are also provided with a diagnosis control circuit 31 for controlling diagnosis by the diagnosis mode signal. , 51.

Then, each LSI 10, 30 and 50
Has a function of disabling the output signal by an external reset signal when the power is turned on, and the LSI 10 in the previous stage has a diagnostic mode signal to the LSI 30 set in the next stage according to a preset order. 1 is output to the signal line 21. The LSI 30 set in the next stage is L in the previous stage.
When receiving the diagnostic mode signal 1 from the SI 10, the prearranged data A is output to the data signal line 12, and the pre-arranged LSI 10 acquires the data A acquired from the data signal line 12 of the next-stage LSI 30 and the prearranged data a. Compare and detect the match with.

As a result, the LSI 10 in the preceding stage outputs the diagnostic mode signal 2 and the prearranged data B to the diagnostic mode signal line 22 and the data signal line 12, respectively, when detecting the coincidence of the data a and A. Also, the L in the previous stage
SI10 outputs the diagnostic mode signal 4 to the signal line 24 when detecting a mismatch in the data comparison with the data A,
At the same time that the diagnostic mode signal 4 is output, the diagnostic operation is stopped.

The LSI 30 in the next stage is the LSI 1 in the previous stage.
When the data B taken in from the data signal line 12 of 0 coincides with the previously agreed data b, it has a function of outputting the diagnostic mode signal 3 indicating the termination of the connection diagnosis between the two LSIs 10 and 30 to the signal line 43. If the next-stage LSI 30 receives the diagnostic mode signal 4 or detects a mismatch in the comparison with the data B, it outputs the diagnostic mode signal 5 to the signal line 4
It outputs to 5.

Further, the LSI 30 of the next stage outputs the diagnostic mode signal 3 or the diagnostic mode signal 5 and at the same time starts the diagnosis of the inter-LSI connection of the further stage (the L of the next stage).
It has a function of outputting the diagnostic mode signal 1 to SI, and stops the diagnostic operation when the preceding LSI receives the diagnostic mode signal 3 from the next LSI. Furthermore, the final stage LSI5
When the diagnosis of 0 is completed, the last-stage LSI 50 outputs the diagnosis end mode signal 6 to the foremost-stage LSI 10 on the signal line 66 and stops the diagnosis operation of the last-stage LSI 50. Then, when the LSI 10 at the frontmost stage receives the diagnostic mode signal 6, the presence of an error is confirmed by loading the error flag (diagnostic mode signal 5) received from each LSI. In the figure, 32 is a data signal line between the LSI 30 and the LSI 50, 41, 42 and 44 are diagnostic mode signal lines, and 63 and 65 are diagnostic mode signal lines.

Next, the operation of the above embodiment will be described. At system startup, LSI10, LSI30 and LSI50
Resets the output signals of the signals connected to each by the reset signal. In this state, each LSI is initially diagnosed by the internal diagnosis, and after completion of the initial diagnosis, the diagnostic control circuit 11 inside the LSI 10 outputs the diagnostic mode signal 1 to the diagnostic mode signal line 21. And LS
The diagnostic control circuit 31 inside the I30 uses the diagnostic mode signal line 2
When the diagnostic mode signal 1 is received from 1, the previously agreed data A is output to the data signal line 12.

When the diagnostic control circuit 11 inside the LSI 10 receives the data A from the data signal line 12, it compares the preset data a with the data A to determine whether these two data are equal or not equal. To detect. As a result, the diagnostic control circuit 11 outputs the diagnostic mode signal 2 to the diagnostic mode signal line 22 when the two data A and a are the same, and simultaneously outputs the prearranged data B to the data signal line 12.

When the data A and the data a are compared and a data mismatch is detected, the diagnostic control circuit 11 outputs the diagnostic mode signal 4 to the diagnostic mode signal line 24.
When the diagnostic control circuit 31 inside the LSI 30 receives the diagnostic mode signal 2 and the data B from the diagnostic mode signal line 22 and the data signal line 12, respectively, it compares the data b and the data B, which have been agreed in advance, with these two. Detects if the data are equal or not equal.

The diagnostic control circuit 31 outputs a diagnostic mode signal 3 to the diagnostic mode signal line 43, which indicates that the diagnosis of the inter-LSI connection has been completed when the two data are equal. Also, 2
When the two data B and b are not equal, or when the diagnostic mode signal 4 is received from the diagnostic mode signal line 24, the diagnostic control circuit 31 outputs the diagnostic mode signal 5 to the diagnostic mode signal line 45. Diagnostic control circuit 1 inside LSI 10
1 receives the diagnostic mode signal 3 from the diagnostic mode signal line 43 and stops the diagnostic operation of the LSI 10.

The diagnostic control circuit 3 inside the LSI 30
1 outputs the diagnosis mode signal 3 or the diagnosis mode signal 5, and at the same time, starts diagnosis of the connection between the LSI 30 and the LSI 50. The connection diagnosis between the LSI 30 and the LSI 50 is L
The diagnosis is performed in the same manner as the diagnosis of the connection between the SI 10 and the LSI 30.
And the diagnostic mode signal 5 is output to the diagnostic mode signal line 66 at the same time as the diagnostic mode signal 5 is output.

As a result, the LSI 10 which is the frontmost LSI
Upon receiving the diagnostic mode signal 6 from the diagnostic mode signal line 66, the internal diagnostic control circuit 11 receives the LSI 10 and the LSI 3 from each other.
The diagnostic mode signal 5 indicating that an error has occurred in the connection with 0 and the diagnostic mode signal 5 indicating that an error has occurred between the LSI 30 and the LSI 50 are loaded and the existence of the error is confirmed. By thus confirming the existence of the error, it is possible to identify which LSI and the connection between the LSIs have an error.

[0017]

As described above, according to the present invention, when a plurality of LSIs are mounted on the board, the inter-LSI connection is diagnosed after the internal diagnosis of each LSI at the system startup is completed. This makes it possible to specify which LSI and which LSI have a connection error.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

[Explanation of symbols]

 10 LSI 11 Diagnostic Control Circuit 12 Data Signal Line 21 Diagnostic Mode Signal Line 22 Diagnostic Mode Signal Line 24 Diagnostic Mode Signal Line 30 LSI 31 Diagnostic Control Circuit 32 Data Signal Line 41 Diagnostic Mode Signal Line 42 Diagnostic Mode Signal Line 44 Diagnostic Mode Signal Line 44 45 diagnostic mode signal line 50 LSI 51 diagnostic control circuit 63 diagnostic mode signal line 65 diagnostic mode signal line 66 diagnostic mode signal line

Claims (1)

[Claims] 1. In a device composed of a plurality of LSIs, two data are compared inside each LSI to detect a coincidence of both signals and to diagnose the connection between the LSIs. Equipped with a diagnostic control circuit that has the function of outputting predetermined data, and compares the data output from the diagnostic control circuit of one LSI with the data output from the diagnostic control circuit of the other LSI after the initial diagnosis is completed. By doing so, the inter-LSI connection diagnosis method is characterized in that if the data match, the connection between the LSIs is diagnosed as normal, and if the data does not match, the failure occurrence is detected.