JP2000206202A - Simple type boundary scan controlling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a boundary scan controlling device which is connected with a boundary scan chain and made to execute a simple boundary scan command like the starting of self-test function of an IC containing boundary scan mechanism. SOLUTION: A simple type boundary scan controlling device 4 which is provided with a storing device 8 for storing boundary scan commands and observed results, a starting device 5 which indicates execution of the boundary scan command, a selecting device 7 which interprets the command and leads out the boundary scan command, and an input and output device 9 which outputs the boundary scan command to a boundary scan chain and stores the observed result is installed on a printed board 2. Execution of a series of the boundary scan commands which are previously stored in the storing device 8 is indicated by using the starting device 5. The selecting device 7 leads out the boundary scan commands from the storing device 8. The input and output device 9 outputs the boundary scan commands to the boundary scan chain in sequence and stores observed results by indication.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC having a boundary scan mechanism formed by connecting an IC having a boundary scan mechanism and an IC having a boundary scan mechanism on a printed circuit board with a daisy chain. The present invention relates to a boundary scan control device used to execute a simple boundary scan instruction such as activation of a self-test function or reading of a specific register in an IC.

[0002]

2. Description of the Related Art Boundary scan is based on JTAG (Joi).
nt Test Action Group). By adopting this standard, an IC on a printed circuit board can be accessed from an edge connector, thereby eliminating the need for an expensive in-circuit tester. It can also test ICs that are difficult to set up test probes such as surface mount components. The use of self-diagnostic functions on printed circuit boards has been increasing, which has led to their widespread use. FIG. 9 shows a test system in which a boundary scan method is employed for testing a printed circuit board as an example of the prior art.

A boundary scan chain is formed by connecting an IC with a boundary scan mechanism and an IC with a boundary scan mechanism compatible with the boundary scan method by a daisy chain, and connected to the edge connector 22 of the printed circuit board 21.
In step 3, the input signal is controlled, and the observation result of the output signal is compared with the expected value in the boundary scan control device 23, so that there is no open / short due to soldering to the wiring of the IC with the boundary scan mechanism. It can be determined whether it operates as specified. FIG. 10 is a schematic diagram in which ICs with a boundary scan mechanism are connected by a daisy chain. If the IC with the boundary scan mechanism has a self-test function, the self-test function is activated and tested through the boundary scan churn, so that the test quality can be further improved.

On a printed circuit board on which a circuit such as a CPU having an important function for controlling the entire system is mounted, a system monitoring device is mounted to constantly monitor the operation of the circuit and detect a failure at an early stage. May be done. Even when a failure is detected by this system monitoring device, the location of the failure on the printed circuit board where the failure is detected is performed using the boundary scan control device connected to the boundary scan chain.

[0005]

However, there are the following problems in the case of testing a printed circuit board or investigating a fault location using a boundary scan control device.

[0006] Except when it is necessary to incorporate many test patterns such as a soldering quality test or an IC function test for an IC mounted on a printed circuit board, it is easy to activate a self-test function of the IC and read a specific register in the IC. Even when such a command is executed, it must be executed from a dedicated boundary scan control device connected to the boundary scan chain of the printed circuit board, which reduces the simplicity which is a feature of the boundary scan method.
Furthermore, in the case of a sudden device failure, it is difficult to connect a boundary scan control device in advance,
New countermeasures were needed.

Further, even if a fault is detected by the system monitoring device, the fault may not be reproduced due to an intermittent fault or the like in many cases by restarting the system to connect the boundary scan control device. There has been a need for a boundary scan control device capable of executing a simple boundary scan instruction for investigating a fault location.

[0008] Therefore, the subject of the present application is the following three items. Boundary scan that can execute simple boundary scan instructions such as activating the self-test function of the IC and reading specific registers in the IC without using a dedicated boundary scan control device, and can also store observation results. Proposing a control device to enhance simplicity.

[0009] In case of sudden equipment failure, I
To be able to read a specific register in C to enable quick response to a failure.

[0010] The system monitoring device detects a fault and at the same time can execute a series of simple boundary scan instructions for investigating a fault location, thereby enabling immediate response to an intermittent fault.

[0011]

In order to solve the above-mentioned problems, the present invention has proposed the following method.

According to the present invention, a storage device for storing a boundary scan instruction and an observation result, an activation device for instructing execution of the boundary scan instruction, an instruction interpreting the instruction, and sequentially taking out a boundary scan instruction corresponding to the instruction from the storage device, The transmitting device and the transmitted boundary scan command are sequentially transmitted to the boundary scan chain, and the observation result returned from the boundary scan chain thereafter when the storage of the observation result in the storage device is specified by the boundary scan instruction. A simple boundary scan control device having an input / output device for storing the data in a storage device, and a simple boundary scan control device provided on a printed circuit board, and instructing the execution of a series of boundary scan commands stored in the storage device in advance by using an activation device. , The selection device interprets the instructions and a series of bounds matching the instructions from the storage device. Scan instructions are sequentially fetched and transmitted to the input / output device, and the input / output device sequentially transmits the transmitted boundary scan instruction to the boundary scan chain, and when the storage of the observation result in the storage device is specified by the boundary scan instruction. Thereafter, the observation results returned from the boundary scan chain are sequentially stored in the storage device, and a simple boundary scan instruction can be executed without connecting a dedicated boundary scan control device externally, and the observation results are also stored. The simplicity is enhanced by doing so. In addition, even in case of a sudden device failure, a specific register in the IC can be read on the spot, thereby enabling quick response to the failure.

When there is a storage device connected to the input / output device outside the simplified boundary scan control device on the printed circuit board, the observation result is stored in the storage device by a boundary scan instruction. , The input / output device sequentially stores the observation results in its storage device, so that a storage device outside the simplified boundary scan control device can also be used as a storage location of the observation results.

Further, the simplified boundary scan control device is installed on the same printed circuit board as the system monitoring device, and the simplified type boundary scan control device transmits information between the system monitoring device and the selection device. If you have a device and are connected to a system monitoring device,
The system monitoring device instructs the selection device via the connection device to execute a series of boundary scan instructions for investigating a failure location previously stored in the storage device of the simplified boundary scan control device at the same time as the failure detection, and selects the selection device. Interprets the instruction, sequentially retrieves a series of boundary scan instructions corresponding to the instruction from the storage device and transmits it to the input / output device, and the input / output device sequentially transmits the transmitted boundary scan instruction to the boundary scan chain, When the storage of the observation result in the specified storage device is specified by the boundary scan instruction, the observation results returned from the boundary scan chain are sequentially stored in the specified storage device, and the failure location is detected simultaneously with the failure detection. To execute a series of simple boundary scan instructions for immediate response to intermittent failures It is.

On the other hand, the simplified type boundary scan control device includes the connection device for transmitting information between a device installed outside the printed circuit board and capable of designating and executing a boundary scan command and the selection device. When connected to a device capable of designating and executing a boundary scan instruction, a device capable of designating and executing a boundary scan instruction can directly designate and instruct an arbitrary series of boundary scan instructions to execute the above. In the simplified boundary scan control device, the selection device receives the instruction via the connection device, and the selection device interprets the instruction,
When it is recognized that the instruction is from a device capable of designating and executing a boundary scan instruction, the designated series of boundary scan instructions are sequentially transmitted to the input / output device, and the input / output device transmits the transmitted boundary scan instruction to the boundary scan instruction. When the observation result returned from the boundary scan chain is sequentially stored in the specified storage device when the storage to the specified storage device of the observation result is designated by the boundary scan instruction, the observation result is sequentially transmitted to the scan chain, The boundary scan command to be executed is not required to be stored in advance in the storage device of the simplified boundary scan control device, so that it can be immediately executed.

Further, when the device capable of designating and executing the boundary scan instruction has a large-capacity storage device, the input / output device can store the observation result in the large-capacity storage device by the boundary scan instruction. The observation result returned from the boundary scan chain after specified is sequentially stored in a large-capacity storage device of a device capable of designating and executing a boundary scan instruction via the selection device and the connection device, and A large amount of observation results that cannot be stored in the storage device of the simplified boundary scan control device can be stored.

[0017]

FIG. 1 is a block diagram showing the principle of the present invention.

The present invention comprises a boundary scan instruction designation / execution instructing device 1, a system monitoring device 3 on a printed circuit board 2, a simplified boundary scan control device 4, a storage device A10, and a boundary scan chain.

When the boundary scan instruction designation / execution instruction device 1 is connected to the simplified boundary scan control device 4, the boundary scan instruction designation / execution instruction device 1
A series of boundary scan commands specified by the above can be instructed to the simplified boundary scan control device 4 to be immediately executed. When a large-capacity storage device B11 is provided therein, a large amount of observation results that cannot be stored in the storage device 8 can be stored. Any device such as a personal computer may be used as long as it has a designation and execution instruction of the boundary scan command and a storage device.

The system monitoring device 3 is installed on a printed circuit board to monitor a specific control circuit. When the system monitoring device 3 is connected to the simplified boundary scan control device 4, it detects an abnormality and, at the same time, sends the detected signal to the simplified boundary scan control device 4. An instruction is issued to execute a series of simple boundary scan instructions for fault location investigation.

The simplified boundary scan control device 4 comprises an activation device 5, a connection device 6, a selection device 7, a storage device 8, and an input / output device 9.

The activation device 5 issues an instruction to execute a series of boundary scan instructions stored in the storage device 8 in advance.

The connection device 6 is connected when the system monitoring device 3 is installed on the printed circuit board 2 or when the boundary scan command designation / execution instruction device 1 is provided outside the printed circuit board 2. 7 and information transmission.

When receiving an execution instruction from the activation device 5 or the system monitoring device 3, the selection device 7 interprets the instruction, sequentially retrieves a series of boundary scan instructions corresponding to the instruction from the storage device 8, and sends it to the input / output device 9. introduce. Further, when an execution instruction is received from the boundary scan instruction designation / execution instructing device 1, the received series of boundary scan instructions are sequentially transmitted to the input / output device 9.

The storage device 8 stores a boundary scan command and an observation result.

The input / output device 9 sequentially transmits the boundary scan command transmitted from the selection device 7 to the boundary scan chain. When the storage of the observation result is designated by the boundary scan command, the input / output device 9 is returned from the boundary scan chain thereafter. The observation result is sequentially stored in any one of the storage device 8, the storage device A10, and the storage device B11 according to the designated storage destination.

The storage device A10 is an arbitrary storage device installed on the printed circuit board 2 and connected to an input / output device.

Next, based on the configuration diagram of FIG. 1, a simplified boundary scan control device according to the present invention can execute a simple boundary scan instruction and store observation results without using a dedicated boundary scan control device. The processing of No. 4 will be described below.

First, the activation device 5 is operated to instruct the selection device 7 to execute a series of boundary scan instructions stored in the storage device 8 in advance.

The selecting device 7 interprets the instruction, retrieves a series of boundary scan instructions corresponding to the instruction from the storage device 8, and sequentially transmits them to the input / output device 9.

The input / output device 9 sequentially transmits the transmitted boundary scan command to the boundary scan chain,
When the storage of the observation results in the storage device 8 is designated by the boundary scan instruction, the observation results returned from the boundary scan chain thereafter are sequentially stored in the storage device 8.

As described above, the simplified boundary scan control device 4 uses the activation device 5 to instruct the selection device 7 to execute a series of boundary scan instructions stored in the storage device in advance, and the selection device 7 issues the instruction. Interpretation takes out a series of boundary scan instructions matching the instruction from the storage device 8 and sequentially transmits them to the input / output device 9, and the input / output device 9 sequentially transmits the transmitted boundary scan instructions to the boundary scan chain, and performs the boundary scan. When the storage of the observation result in the storage device 8 is specified by the instruction, the observation result returned from the boundary scan chain is sequentially stored in the storage device 8 without using a dedicated boundary scan control device. A simple boundary scan instruction can be executed, and observation results can be stored, thereby improving simplicity. In addition, even in case of a sudden device failure, a specific register in the IC can be read on the spot, thereby enabling quick response to the failure.

If there is an arbitrary storage device A10 connected to the input / output device 9 on the same printed circuit board 2 as the simplified type boundary scan control device 4, a storage device for the observation result is issued by the boundary scan instruction. By specifying the storage in A10, the input / output device 9 stores the observation result returned from the boundary scan chain in the storage device A10 after the storage of the observation result in the storage device A10 is designated by the boundary scan instruction. I do. As a result, any storage device installed outside the simplified boundary scan control device 4 on the printed circuit board 2 and connected to the input / output device 9 can be used as a storage location for observation results.

When the system monitoring device 3 is installed on the printed circuit board 2 and connected to the simplified boundary scan control device 4 based on the configuration diagram of FIG. At the same time, a description will be given of a process for executing a series of simple boundary scan instructions for investigating a fault location as follows.

First, the system monitoring device 3 monitors a specific control circuit on the printed circuit board 2, and when a failure is detected, sends an instruction for executing a series of simple boundary scan instructions for investigating a failure location to the connection device 6.

The connection device 6 transmits an instruction to the selection device 7.

The selection device 7 interprets the instruction, retrieves a series of boundary scan instructions corresponding to the instruction from the storage device 8, and sequentially transmits the instructions to the input / output device 9.

The input / output device 9 sequentially transmits the transmitted boundary scan commands to the boundary scan chain,
When the storage of the observation result is specified by the boundary scan instruction, the observation results sent from the boundary scan chain thereafter are sequentially stored in the specified storage device.

As described above, the system monitor installed on the printed circuit board is connected to the simplified boundary scan controller 4, and the failure is detected by the simplified boundary scan controller 4 at the same time as the failure of the system monitor 3 is detected. For the execution of a series of simple boundary scan instructions, the simplified boundary scan controller sequentially sends the series of designated boundary scan instructions to the boundary scan chain, and the storage of observation results is specified by the boundary scan instruction. In such a case, the observation results are sequentially stored in a designated storage device, thereby making it possible to cope with an intermittent failure.

On the other hand, when the boundary scan instruction designation / execution instructing device 1 is connected to the simplified boundary scan control device 4 based on the configuration diagram of FIG. 1, a series of boundary scan instructions to be executed in advance are stored in the storage device 8. The following describes the processing of the simplified boundary scan control device 4 of the present invention that enables a series of boundary scan instructions to be executed immediately without storing it.

The boundary command designation / execution instructing device 1 is started, a series of boundary scan commands to be executed are designated, and the execution is instructed to the connection device 6 of the simplified boundary scan control device 4.

The connection device 6 transmits an instruction to the selection device 7.

The selecting device 7 interprets the instruction and, when recognizing that the instruction is from the boundary instruction designating / executing instruction device 1, sequentially transmits a series of designated boundary scan instructions to the input / output device 9.

The input / output device 9 sequentially transmits the transmitted boundary scan command to the boundary scan chain,
When the storage of the observation result is specified by the boundary scan instruction, the observation results returned from the boundary scan chain thereafter are sequentially stored in the specified storage device.

As described above, the boundary scan instruction designation / execution instructing device 1 is connected to the simplified boundary scan control device 4, and a series of boundary scan instructions to be executed by the boundary scan instruction designation / execution instructing device 1 are designated. When the simple boundary scan control device 4 instructs the simple boundary scan control device 4 to execute the instruction, and recognizes that the instruction is that of the boundary scan instruction designation / execution instructing device 1, the simple boundary scan control device 4 performs a series of boundary scan instructions instructed. When the observation results are sequentially transmitted to the chain and the storage of the observation results is designated by the series of boundary scan instructions, the observation results are sequentially stored in the designated storage device, whereby the storage device of the simplified boundary scan control device 4 is previously stored. 8 stores a series of boundary scan instructions to be executed. Even without first, so that it is immediately executed.

When the boundary scan instruction designating / executing instruction device 1 includes a large-capacity storage device B11, the storage device B1 of the observation result is obtained by the boundary scan instruction.
1, the input / output device 9 transmits the observation result returned from the boundary scan chain to the storage device B11 when the storage of the observation result in the storage device B11 is designated by the boundary scan instruction. Store. Thus, a large amount of observation results that cannot be stored in the storage device 8 can be stored.

[0047]

Next, an embodiment of the present invention will be described in which a simplified boundary scan control according to the present invention is capable of executing a simple boundary scan instruction and storing observation results without using a dedicated boundary scan control device. The device will be described with reference to the drawings.

First, a configuration diagram in which a simplified boundary scan control device is installed on a printed circuit board will be described as one embodiment of the present invention with reference to FIG.

This configuration diagram is composed of a simplified boundary scan control device 4 installed on the printed circuit board 2, a storage device A10, and a boundary scan chain.

The simplified boundary scan control device 4 comprises an activation device 5, a selection device 7, a storage device 8, and an input / output device 9.

The activation device 5 issues an instruction to execute a series of boundary scan instructions stored in the storage device 8 in advance.

The selecting device 7 interprets the instruction, retrieves a series of boundary scan instructions corresponding to the instruction from the storage device 8, and sequentially transmits the instructions to the input / output device 9.

The storage device 8 stores a boundary scan command and an observation result. FIG. 5 shows an example of the contents of a storage device of the simplified boundary scan control device as one embodiment of the present invention. A series of boundary scan instructions are stored from the start of the IC-A circuit test in the area, and the observation result storage area stores the observation result output from the boundary scan chain by designation. In addition, IC-A
The start of the circuit test means a boundary scan instruction designating activation of a self-test function of an IC located at a specific position on the printed circuit board.

The input / output device 9 sequentially transmits the boundary scan command transmitted from the selection device 7 to the boundary scan chain on the printed circuit board 2 or when the storage of the observation result is designated by the boundary scan command. The observation results returned from the boundary scan chain are sequentially stored in a specified storage device.

The storage device A 10 is provided outside the simplified boundary scan control device 4 on the printed circuit board 2 and is an arbitrary storage device connected to the input / output device 9.

FIG. 6 is a flowchart of one embodiment of the present invention. Next, a description will be given of processing of the simplified boundary scan control device which can execute a simple boundary scan instruction and store observation results without using a dedicated boundary scan control device with reference to FIG. In addition, when there is an arbitrary storage device connected to the input / output device outside the simplified boundary scan control device on the printed circuit board, a process that can be used as a storage location of the observation result will be described.

Step ST01: Execution of a series of boundary scan commands stored in the storage device 8 is instructed by pressing a switch of the activation device 5.

Step ST02: The selecting device 7 interprets the instruction, and recognizes the head of a series of boundary scan instructions stored in the storage device 8 in advance and matching the instruction as a read position.

Step ST03: The selecting device 7 reads one boundary scan command from the read position of the storage device 8 and transmits it to the input / output device 9.

Step ST04: The input / output device 9 transmits the transmitted boundary scan command to the boundary scan chain, and if the storage of the observation result in the storage device 8 has been specified by the boundary scan command first, the boundary scan chain. The observation result returned from the storage device 8
To store. The storage device A10 connected to the input / output device 9 exists outside the simplified boundary scan control device 4 on the printed circuit board 2, and the storage of the observation result in the storage device A10 is designated by the boundary scan command. In this case, the input / output device 9 stores the observation result returned from the boundary scan chain in the storage device A10.

Step ST05: The selecting device 7 judges whether the immediately preceding boundary scan instruction is the last instruction of a series of boundary scan instructions, and terminates the processing if it is the last instruction, otherwise proceeds to step ST06. move on.

Step ST06: The selection device 7 updates the read position so that the next boundary scan instruction stored in the storage device 8 can be read. Then, step ST03
Return to

The simplified boundary scan control device of the present invention uses an IC on a boundary scan chain of a printed circuit board without using a dedicated boundary scan control device.
The present invention can be applied to a case where a simple boundary scan instruction such as activation of a self-test function of a particular IC or reading of a specific register in an IC is executed or an observation result is stored.

Next, an embodiment of the present invention will be described in which a simple boundary scan control device and a system monitoring device are installed and connected on a printed circuit board. The processing of the simplified boundary scan control device that can execute a series of simple boundary scan instructions will be described with reference to the drawings.

First, a configuration diagram in the case where the simplified boundary scan control device and the system monitoring device are connected will be described as one embodiment of the present invention with reference to FIG.

This configuration diagram includes a system monitoring device 3, a CPU 12, a simplified boundary scan control device 4, and a boundary scan chain installed on a printed circuit board 2.

The system monitoring device 3 monitors the operation of the CPU 12, which is a central processing unit, and when an abnormality is detected, the simple boundary scan control device 4 executes a series of simple boundary scan instructions for investigating a fault location. To instruct.

The simplified boundary scan control device 4 comprises a connection device 6, a selection device 7, a storage device 8, and an input / output device 9.

The connection device 6 transmits information between the system monitoring device 3 and the selection device 7.

The selecting device 7 interprets the instruction, and stores it in the storage device 8.
, A series of boundary scan instructions corresponding to the instruction are taken out and sequentially transmitted to the input / output device 9.

The storage device 8 stores a boundary scan command and an observation result.

The input / output device 9 sequentially transmits the boundary scan command transmitted from the selection device 7 to the boundary scan chain, and is returned from the boundary scan chain thereafter when the storage of the observation result is designated by the boundary scan command. The observation results are sequentially stored in the designated storage device.

FIG. 7 is a flowchart of another embodiment of the present invention. Next, the processing of the simplified boundary scan control device which is capable of executing a series of simple boundary scan instructions for investigating a fault location in accordance with an instruction from the system monitoring device will be described with reference to FIG.

Step ST11: The system monitoring device 3 monitors the operation of the CPU 12, and when an abnormality is detected,
The simple boundary scan control device 4 is instructed to execute a series of simple boundary scan instructions for investigating a fault location to the selection device 7 via the connection device 6.

Step ST12: The selecting device 7 interprets the instruction and recognizes the head of a series of boundary scan instructions stored in advance in the storage device 8 and matching the instruction as a read position.

Step ST 13: The selecting device 7 reads one boundary scan command from the read position of the storage device 8 and transmits it to the input / output device 9.

Step ST14: The input / output device 9 transmits the transmitted boundary scan command to the boundary scan chain, and if the storage of the observation result in the storage device 8 is specified by the boundary scan command first, the boundary scan chain. The observation result returned from the storage device 8
To store.

Step ST15: The selecting device 7 judges whether the immediately preceding boundary scan instruction is the last one of a series of boundary scan instructions, and terminates the processing if it is the last instruction, otherwise proceeds to step ST16. move on.

Step ST16: The selecting device 7 updates the read position so that the next boundary scan command stored in the storage device 8 can be read. Then, step ST13
Return to

The simplified boundary scan control device of the present invention can execute a simple boundary scan command by connecting to a device related to the boundary scan control device such as a system monitoring device inside a printed circuit board.
The present invention can also be applied to storing observation results.

Further, in the case where a personal computer capable of designating and executing a boundary scan command is connected to a simple boundary scan control device outside the printed circuit board, an embodiment of the present invention may be applied to a simple boundary scan control device. With reference to the drawings, a description will be given, with reference to the drawings, of a simplified boundary scan control device capable of executing a boundary scan instruction by immediate execution without storing a series of boundary scan instructions to be executed in advance in the storage device.
In addition, when the personal computer has a large-capacity storage device, processing of the simplified boundary scan control device that enables storage of a large amount of observation results that cannot be stored in the storage device of the simplified boundary scan control device will also be described. .

First, based on FIG. 4, as an embodiment of the present invention, it is assumed that the simplified boundary scan control device can specify and execute a boundary scan instruction and is connected to a personal computer having a large-capacity storage device. The configuration diagram will be described.

This configuration diagram includes a personal computer 13, a simplified boundary scan control device 4 on the printed circuit board 2, and a boundary scan chain.

The personal computer 13 has a large-capacity storage device B11, and stores an observation result when a boundary scan instruction is specified and executed, and when specified by the boundary scan instruction.

The simplified boundary scan control device 4 includes a connection device 6, a selection device 7, a storage device 8, and an input / output device 9.

The connection device 6 is provided between the personal computer 13 and the selection device 7 to transmit information.

The selecting device 7 interprets the instruction, and when the instruction is recognized as being from the personal computer 13, sequentially transmits the designated series of boundary scan instructions to the input / output device 9.

The storage device 8 stores a boundary scan command and an observation result.

The input / output device 9 sequentially transmits the boundary scan command transmitted from the selection device 7 to the boundary scan chain, and is returned from the boundary scan chain thereafter when the storage of the observation result is designated by the boundary scan command. The observation results are sequentially stored in the designated storage device.

FIG. 8 is a flowchart of another embodiment of the present invention. Next, based on the same figure, a series of boundary scan instructions specified on the personal computer can be converted to a simple boundary scan instruction without storing a series of boundary scan instructions to be executed in the storage device of the simplified boundary scan control device in advance. If the personal computer is equipped with a large-capacity storage device, the storage device of the simplified boundary scan control device can specify the observation result storage destination by using a boundary scan instruction. The processing of the simplified boundary scan control device capable of storing a large amount of observation results that cannot be performed will be described below.

Step ST21: A series of boundary scan commands to be executed on the screen of the personal computer 13 are input, and the execution is instructed to the selection device 7 via the connection device 6.

Step ST22: The selecting device 7 interprets the instruction, and when recognizing the instruction from the personal computer 13, recognizes the head of a series of boundary scan instructions received together with the instruction as the execution position.

Step ST23: The selection device 7 transmits the boundary scan instruction at the execution position of the series of boundary scan instructions to the input / output device 9.

Step ST24: The input / output device 9 transmits the transmitted boundary scan command to the boundary scan chain, and the observation returned from the boundary scan chain when the storage of the observation result is previously specified by the boundary scan instruction. Store the result in the specified storage device. When the personal computer 13 has a large-capacity storage device B11 and the storage of the observation result in the storage device B11 is specified by the boundary scan command,
The observation result returned from the boundary scan chain is stored in the storage device B11 via the selection device 7 and the connection device 6.

Step ST25: The selecting device 7 determines whether the boundary scan command transmitted immediately before is the last command of a series of boundary scan commands, and terminates the processing if the last command is the last command, otherwise proceeds to step ST26. move on.

Step ST26: The selecting device 7 updates the execution position so that a boundary scan instruction next to the designated series of boundary scan instructions can be transmitted. Thereafter, the process returns to step ST23.

[0097]

As described above, the simplified boundary scan control device according to the present invention does not require the use of a dedicated boundary scan control device, but can be a simple boundary such as activating a self-test function of an IC on a boundary scan chain or reading a specific register in the IC. The scan instruction can be executed and the observation result can be stored, which is effective in improving simplicity. In addition, even in the case of a sudden device failure, a specific register in the IC can be read on the spot, which is effective in promptly dealing with the failure.

Further, when the simplified boundary scan control device according to the present invention is connected to a system monitoring device installed on the same printed circuit board, a simple fault detection by the system monitoring device and a simple fault investigation can be performed. The ability to execute a series of boundary scan instructions is effective in dealing with intermittent failures.

[Brief description of the drawings]

FIG. 1 is a principle configuration diagram of the present invention.

FIG. 2 is a configuration diagram of one embodiment of the present invention.

FIG. 3 is a configuration diagram of another embodiment of the present invention.

FIG. 4 is a configuration diagram of another embodiment of the present invention.

FIG. 5 is an example of the contents of a storage device of the simplified boundary scan control device as one embodiment of the present invention.

FIG. 6 is a flowchart of one embodiment of the present invention.

FIG. 7 is a flowchart of another embodiment of the present invention.

FIG. 8 is a flowchart of another embodiment of the present invention.

FIG. 9 shows a test system in which a boundary scan method is used for testing a printed circuit board as an example of a conventional technique.

FIG. 10 is a schematic diagram of a daisy chain of an IC with a boundary scan mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Boundary scan command designation / execution instruction device 2 Printed circuit board 3 System monitoring device 4 Simple type boundary scan control device 5 Starting device 6 Connecting device 7 Selection device 8 Storage device 9 Input / output device 10 Storage device A 11 Storage device B 12 CPU 13 PC

Claims (5)

[Claims] An IC with a boundary scan mechanism and an IC with a boundary scan mechanism on a printed circuit board (2)
Connected to a boundary scan chain formed by daisy chaining, and to execute a simple boundary scan instruction such as activation of a self-test function or reading of a specific register in the IC with respect to an IC having a boundary scan mechanism. A storage device (8) for storing a boundary scan command and an observation result, and a series of boundary scan commands stored in advance in the storage device (8) to the selection device (7). An activation device (5) to be executed and an instruction of the activation device (5) are interpreted, a series of boundary scan instructions corresponding to the instruction are sequentially retrieved from the storage device (8), and selected to be transmitted to the input / output device (9). Device (7), and a boundary scan chain transmitted from the selection device (7). An input / output device for sequentially transmitting the observation results returned from the boundary scan chain to the storage device (8) when the storage of the observation results in the storage device (8) is designated by the boundary scan instruction. (9) A simplified type boundary scan control device, comprising: 2. The simple type boundary scan control device according to claim 1, wherein the storage device A includes a storage device A on the same printed circuit board.
In the case where the input / output device (9) is connected to the input / output device (9), the input / output device (9) receives the observation result in the storage device A (10) by the boundary scan instruction, and thereafter performs the boundary operation. The simplified boundary scan control device according to claim 1, wherein the observation results returned from the scan chain are sequentially stored in a storage device (10). 3. The simplified boundary scan control device includes a connection device (6) for transmitting information between a system monitoring device (3) and a selection device (7), and is connected to the system monitoring device (3). When a selection instruction (7) receives an instruction to execute a series of boundary scan instructions for fault location investigation from the system monitoring device (3), the selection device (7) interprets the instruction of the system monitoring device (3) and stores the instruction in the storage device (8). 3. A simplified boundary scan control device according to claim 1, wherein a series of boundary scan instructions for investigating a fault location corresponding to the instruction are sequentially taken out and transmitted to the input / output device (9). . 4. A simplified boundary scan control device comprising: a connection device for transmitting information between a boundary scan instruction designation / execution instructing device and a selection device; and a boundary scan instruction designation device. When receiving an instruction to execute a series of boundary scan instructions connected to the execution instruction device (1), the selection device (7) interprets the instruction and designates the boundary scan instruction and an instruction from the execution instruction device (1). 3. The simplified boundary scan control device according to claim 1, wherein a series of designated boundary scan commands is sequentially transmitted to the input / output device when the recognition is made. 5. When the boundary scan command designation / execution instructing device (1) includes a large-capacity storage device B (11), the input / output device (9) uses the boundary scan command to store an observation result storage device B (11). The simplified boundary scan control according to claim 4, characterized in that, when the storage in (11) is designated, the observation results returned from the boundary scan chain after that are sequentially stored in the storage device (B). apparatus.