JPS60233576A - Diagnosing device of controlling device - Google Patents

Abstract

PURPOSE:To enable a diagnosis of a defective LSI with a simple logical circuit by comparing the output of each LSI with the output of other LSI by a simultaneous scanning-in of the same pattern data. CONSTITUTION:The outputs of LSIs 5-7 according to the diagnosis data simultaneously scanned in from a diagnosis data generating circuit 14 are compared with the outputs of other two sets of LSIs by respectively comparative circuits 22-24 and in case of dissidence, the outputs of the circuits 22-24 are turned over to a logic 1 and fed to a display controlling circuits 25-27 and a display is lit. A diagnosis is performed as to which LSI is defective with a simple logical construction by the combination of the display lighting.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a diagnostic device for a control device that diagnoses a plurality of LSIs (Large Scale Semiconductor Integrated Circuits) constituting the control device.

``Prior Art'' Diagnosis of a conventional control device has been performed by dividing the plurality of cages that make up the control device.

However, in recent years, as information processing devices have become more and more integrated into LSIs, the conventional configuration of a plurality of packages is being replaced by a plurality of LSIs.

For this reason, diagnosis of a control device is changing from diagnosis of the control device's electronics to diagnosis of a plurality of LSIs in functional units constituting the control device.

However, conventionally, there has been no system for diagnosing which LSI is malfunctioning among these LSIs.

“Object of the invention” The object of the invention is to
In contrast, it is an object of the present invention to provide a diagnostic device capable of diagnosing which LSI is malfunctioning using a simple logic circuit.

"Structure of the Invention" According to this invention, a plurality of LSIs having a scan path
The diagnostic device for the control device comprises a diagnostic data generation circuit capable of simultaneously sending the same diagnostic data to the data inputs for the plurality of I and SII scan paths, and a diagnostic data generation circuit for the plurality of LSI scan paths. It consists of a comparison circuit group that compares the output data from two LSIs among the output data from the campus data output, and a display control circuit group that displays the comparison results from this comparison circuit group.

"Example" Next, the present invention will be explained in detail with reference to the drawings.

An embodiment of this invention is shown in FIG. The control device is composed of a plurality of LSI 5 , LSI 6 , I, Sr1, and these LSI 5 , LSI 6 , LS
I7 has a scan path, and the number of flip-flops for the scan path is the same for each LSI.

The clock signal from the oscillation circuit 11 passes through the dart circuit 12 to the counter control circuit 13, pattern generation circuit (diagnostic data generation circuit) 14, LSI5, LSI6, and LSI
7 via lines 15, respectively.

All circuits and LSIs are reset before starting the diagnosis, and the LSI is set to a scanning operation state.

In the pattern generation circuit 14, a certain data pattern is preset in an initial state, and the pattern generation circuit 14 performs a shifting operation based on a clock signal.

At this time, the output data (diagnosis data) from the pattern generation circuit 14 is sent to the LSI 5, L via the line 16.
It is supplied to SI6 and LSI7 at the same time.

The counter control circuit 13 performs control by counting the clock signal.

That is, the counter control circuit 13 counts twice the number of scan path flip-flops of LSI 5, LSI 6, and LSI 7 that have scan paths,
Control.

The pattern data from the 4-turn generation circuit 14 is
5. The counter of the counter control circuit 13 increases by +1 every time it is input to the scan-in of LSI 6 and LSI 7.
Sanru. LSI 5. When the same number of clock signals as the number of scan path flip-flops in LSI 6 and LSI 7 are input, the first tree 7 data from the pattern generation circuit 14 is transferred to LSI 5 as the clock signals are input. , LSI 6 and LSI
7 scan out via lines 17, 18 and 19, respectively.

Therefore, when twice the number of flock signals as the number of Frizzoff horns for scanning i4 that LSI 5, LSI 6, and LSI 7 have are input, the pattern generation circuit 14
The Noguturn data generated from LSI 5.

They will be output from the scan outs of LS, I6, and LSI7, respectively.

When the counter control circuit 13 counts twice the number of clock signals as the number of flip-flops, the counter control circuit #F-13 inhibits the operation of the gate circuit 11.2 through the line 21, and the counter control circuit #F-13 and the pattern generation circuit Axis; 14, LSI
5. Stop the clock signal being supplied to LSI 6 and LSI 7. Therefore, the scan/'PS operation is canceled at this time.

The scan-out data outputted from LSI 5, LSI 6, and LSI 7 via lines 17, 18, and 19, respectively, are supplied to two of the comparator circuits 22, 23, and 24, respectively, and different LSI output data □ and be compared. That is, each output data from LSI 5 and LSI 6 is supplied to the comparison circuit 22, and LSI 5 and LSI 6
Each output data from SI 7 is supplied to a comparison circuit 23, and each output data from LSI 6 and LSI 7 is supplied to a comparison circuit 24.

Further, each output data of LSI 5, LSI 6, and LSI 7 is compared every time a clock signal is supplied. In these comparisons, if the output data of the two LSIs match, the output of the comparison circuit will be the logic It O, II; if they do not match, the output of the comparison circuit will be the logic 1". This indicates that one of the two LSIs is in a defective state.

Each output signal from the comparison circuits 22, 23, 24 is synchronized with the clock signal, and the display control circuits 25, 26, .
27. If the outputs of the comparison circuits 22, 23 and 24 become the logic It I II even once, this is indicated on the corresponding display control circuits 25, 26 and 27. If LSI5 is defective, LSI5,
The output data of LSI 6 no longer matches, and the LSI
5. If the output data of LSI 7 no longer matches,
The output data from the comparison circuits 22 and 23 is logic II
II, the display control circuits 25 and 2 respectively
Display 6 lights up. This determines that LSI 5 is defective.

In this embodiment, the control device is configured with three LSIs, but in the case of more than three LSIs, each LSI
You can think of it in the same way, just by increasing the number of combinations.

"Effects of the Invention" As explained above, the diagnostic device of the present invention uses the same turn data (
scan in the diagnostic data) at the same time, and
By comparing the output data from the scan-out of the SI with the scan output data of the other two LSIs each time it is scanned, it is possible to easily detect defects in the LSI using a simple logic circuit. There is.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. 5-7...LSI, 11...Oscillation circuit, 12...
Gate circuit, 13... Counter control circuit, 14...
Turn generation circuit as a diagnostic data generation circuit, 22
~24...Comparison circuit, 25-27...Display control circuit. Patent applicant Taku Kusano, agent for NEC Corporation

Claims (1)

[Claims] (1) In a control device composed of a plurality of LSIs having a scan path, a diagnostic data generation circuit capable of simultaneously sending the same diagnostic data to the scan path data inputs of the plurality of LSIs; multiple L
A comparison circuit group that compares the output data from two LSIs among the output data from the scan path data input of the SI, and a display control circuit group that displays the comparison results from the comparison circuit group, A diagnostic device for a control device that diagnoses nine LSIs based on a combination of two LSIs to be compared and the comparison results.