JPS5953585B2 - Scan-in-out control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a scan-in-out control device that reads and writes the contents of registers, flip-flops, etc. in a data processing device.

Data processing equipment generally has a scan-in/out function that reads and writes the contents of registers, flip-flops, etc. within the equipment for maintenance or diagnosis purposes, but if the scan-in/out control unit fails, the failure state can be detected. Since the scan-in-out operation itself becomes invalid, it usually takes a long time until the cause is unknown, and the control unit needs to constantly check the normality during operation.

Incidentally, the scan-in-out control sections include a main control section that exists in one place within the data processing device and controls the entire scan-in-out operation, and a plurality of scan-in-out control sections that are distributed within the device and are transferred from the main control section. In a case where the data processing device is composed of two types of control units: a sub-control unit that holds the transmitted control information and assists scan-in-out operations based on this content, the number of sub-control units increases as the data processing device becomes larger. However, if each sub-control unit is provided with the above-mentioned normality check function, the amount of hardware will inevitably increase, and it is necessary to suppress the increase in hardware as much as possible. The present invention has been made in view of the above circumstances, and by providing a simple selection circuit in each sub-control section and a comparison circuit in the main control section, the present invention can be achieved with a small increase in hardware.
It is an object of the present invention to provide a scan-in-out control device that can check a sub-control unit at the same time as a scan-in-out operation. Briefly speaking, the present invention is characterized by providing means for returning the scan-in-out control information held in the sub-control section to the main control section, and further converting the returned control information in the main control section to the original one. A means for comparing with the information is prepared, and when the scan-in-out data is transferred, the return of the control information and the comparison check are performed at the same time.

Next, one embodiment of the present invention will be described in detail using the drawings.

FIG. 2 is a configuration diagram of one embodiment of scan-in-out control information according to the present invention.

In the figure, the scan-in-out control device is the main control unit 1.
and a sub-control section 2. Furthermore, the main control unit 1 has scan address, scan-in/scan-in-out identification bits;
In addition to the main control register 3 that holds control information such as data, scan-in data, and scan-out data, and the comparison circuit 7 that is one of the features of the present invention, there is also a scan lock control circuit and a control circuit that is not shown in the figure. It consists of a circuit that sends out a signal to identify whether data is being transferred or scan data is being transferred. The sub-control unit 2 includes a sub-control register 4 that holds the transferred control information.
and a selection circuit 6, which is a feature of the present invention. The sub-control section 2 is provided corresponding to, for example, a target register or a package board, and each sub-control section is assigned a unique identification code. Now, during the scan-in-out operation, the main control section 1 first sets a signal (not shown) indicating that control information is being transferred to "1", and sends the control information from the main control register 3 to the path 10 together with the scan tarot.

Each sub-control unit stores the control information sent to it in the sub-control register 4.
It checks whether the identification code in the control information matches its own, and only the sub-control unit with a match is involved in the next scan-in-out data transfer control. That is, when the scan-in/scan-out identification bit specified by the processing device is scan-in, the main control unit 1 sets the signal indicating that scan data is being transferred to "1", and
The scan-in data is sent from the main control register 3 to the path 10 along with the scan 5 young lock. The corresponding sub-control unit 2 transfers this to the target register 5 at the scan address indicated by the sub-control register 4 via the path 12. At this time, when the data width of pass 10 and pass 12 is [■■
The sub-control section 2 not only edits data but also controls the scan clock. When scanning out,
The data enters the selection circuit 6 from the main register 5 via a path 13, and is further transferred to the main control register 3 via a path 11. On the other hand, during scan-in, the control information held in the sub-control information register 4 passes from the path 15 to the selection circuit 6 and then to the comparison circuit 7 via the path 11 in synchronization with the transfer of the scan-in data. Enter one mouth.

The original information of the control information returned from the main control register 3 enters the other port of the comparison circuit 7 via the path 14, and a match check is performed. At the time of scan out, the input of the selection circuit 6 is switched by taking advantage of the delay in the data in the target register 5 reaching the selection circuit 6, and the input of the selection circuit 6 is switched.
is used in Timesure to check for consistency of returned control information in the same way as when scanning. That is, a normality check to determine whether the control information is correctly held in the sub-control register 4 of the sub-control unit 2 is performed in parallel with the scan-in-out operation. Note that if a mismatch occurs in the comparator circuit 7, since a part of the scan address is the identification code of the sub-control unit 2, it is possible to easily isolate the sub-control unit that is the faulty part. As explained above, according to the present invention, the normality check of the sub-control unit can be performed in the same way as the scan-in-out operation, and the selection circuit that should be prepared for this purpose is, for example, when the path 11 is 1 bit wide. There is only a few gates at most per sub-control unit, and the comparison circuit also has about four gates, so the increase in hardware is small.

[Brief explanation of drawings]

The figure is a block diagram of one embodiment of the scan-in-out control device according to the present invention. 1... Main control section, 2... Sub control section, 3
...Main control register, 4...Sub control register, 5...Purpose register, 6...
Selection circuit, 7... Comparison circuit.

Claims (1)

[Claims] 1 A main control unit that exists within a data processing device and controls the entire scan-in/out operation of desired registers, etc. of the device, and a control unit that exists in multiple locations distributed within the data processing device and that is transferred from the main control unit. In a scan-in-out control device comprising a sub-control unit that holds information and assists scan-in-out operations based on the content, the sub-control unit scans in control information transferred from the main control unit and held. The main control unit is provided with a means for sending the data back to the main control unit at the time of out data transfer, and the main control unit compares the control information returned from the sub control unit with the original control information to check the normality of the sub control unit. A scan-in-out control device comprising: means.