JPH0373642A - Protocol test equipment - Google Patents

Abstract

PURPOSE:To analyze the reply of a transmitter-receiver simultaneously in the occurrence of a communication error by superimposing a pattern of a communication error onto a communication data between transmitter-receivers being test objects so as to generate the communication error. CONSTITUTION:A detection circuit 8 detects a timing of communication error generation set by a communication error setting section 9 to which the content of the communication error is set to drive a pattern generating circuit 10 to generate a communication error pattern corresponding to the content of the communication error at the communication error setting section 9 and a pattern is generated from the generating circuit 10 and sent to a transmission line 4 through a transmission circuit 11 and a driver 5. Then how a transmission station 2 and a reception station 3 having a transmitter-receiver reply is monitored trough a receiver 6 and a monitor circuit 7 to analyze whether or not the operation as a protocol is implemented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a protocol test device, and more particularly to a protocol test device that performs a protocol test when an abnormal condition such as a communication error occurs.

[Conventional technology]

Conventionally, when a communication error occurs, such a protocol test device determines by testing whether or not the transmitting/receiving device to be tested performs communication according to the protocol.

FIG. 4 is a block diagram of a protocol test device connected to a transmission line, showing an example of the conventional technology.

As shown in Figure 4, the conventional test system
It is comprised of a transmitting/receiving device 21 connected to this transmission line 4 and to be tested, and a protocol testing device 20. This protocol test device 20 includes a driver 5 and a receiver 6 connected to a transmission path 4, a monitor circuit 7 connected to the receiver 6, a communication error setting unit 9 that sets the contents of communication errors, and It has a frame generation circuit 22 that generates a standard communication error frame based on the content of the communication error, and a transmission circuit 11 that outputs the communication error frame to a transmission line 46. Note that a frame is a communication packet consisting of a source address, a receiving source address, a control code, data, and the like. On the other hand, since the transmitting/receiving device 21 receives the communication error frame and responds, the response contents are sent to the register 6 of the protocol test device 20. received via the monitor circuit 7,
Analyze whether the response to the communication error frame sent earlier is in accordance with the protocol.

FIG. 5 is a schematic diagram for explaining an example of communication between the conventional transmitting station and receiving station in FIG. 4.

As shown in FIG. 5, this communication example shows the exchange of data between a transmitting station having a transmitting/receiving device and a receiving station in a handshake method, where the transmitting station transmits the transmitted data ■ to the receiving station, and the receiving station transmits the transmitted data ■ A response ■ is sent back indicating whether or not the message was received.

Furthermore, the transmitting station transmits transmission data (2) to the receiving station in response to the response (2). Thereafter, the same process is repeated.

For example, the Tomestic Digital Bus (
In D2B), the transmitting station transmits data one byte at a time, and if a response indicating successful data reception is not returned from the receiving station, the same data is transmitted again. Furthermore, if there is a response from the receiving station indicating successful reception, the protocol is such that the next data is transmitted.

FIGS. 6(a) and 6(b) are device connection diagrams for explaining conventional protocol test procedures, respectively.

As shown in FIG. 6(a), when testing such a handshake protocol, conventionally, the transmission data 2 is sent from the protocol test device 20 to the receiving station 3 having the transmitting/receiving device to be tested through the transmission line 4. The response (2) from the receiving station 3 is monitored, and the transmitted data (2) is analyzed to see if it is in accordance with the protocol.

Next, as shown in FIG. 6(b), the protocol test device 220 transmits the response ■ to the transmitting/receiving station 2 having the transmitting/receiving device, and then receives and monitors the transmission data ■ from the transmitting station 2, and the response ■ Analyze whether the protocol is followed or not.

[Problem to be solved by the invention]

When testing a handshake protocol when a communication error occurs using the conventional protocol test equipment described above, the first step is to send a communication error frame from the protocol test equipment to the receiving station of the transmitter/receiver under test. In addition, it is necessary to perform a test to analyze the response from the receiving station, and in the second stage, the protocol test device sends a response to the transmitting station of the transmitting/receiving device when a communication error frame is received, and the transmitting station transmits in response to that response. It is necessary to perform tests to analyze the data.

Therefore, since the conventional protocol test device needs to perform a two-step test, it not only has low test efficiency but also has the drawback of being away from actual communication error conditions.

SUMMARY OF THE INVENTION An object of the present invention is to provide a protocol test device that can improve such test efficiency and test protocols under conditions close to actual communication errors.

[Means to solve the problem]

A protocol test device of the present invention is connected to a transmitting/receiving device via a transmission path, and tests whether or not the transmitting/receiving device responds according to the protocol when a communication error occurs. a communication error setting section that sets the contents of the communication error setting section; a monitor circuit that monitors the data being sent from the transmitting/receiving device onto the transmission path; and a communication error setting section that determines whether a communication error has occurred in the communication error setting section based on the contents monitored by the monitor circuit. a pattern generation circuit that generates a pattern for generating a communication error in the communication error setting section based on the timing of occurrence of the communication error detected by the detection circuit; and the pattern generation circuit. and a transmitting circuit that superimposes a pattern from the above on a transmission path, and generates a communication error by superimposing the communication error pattern on communication data transmitted and received between transmitting and receiving devices connected to the transmission path. It consists of

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a protocol test device connected to a transmission path, showing a first embodiment of the present invention.

As shown in FIG. 1, the protocol test device 1 of this embodiment is connected to a transmission line 4 together with a transmitting/receiving apparatus 2 as a transmitting station and a transmitting/receiving apparatus 3 as a receiving station; The driver 5 and receiver 6 connected to this receiver 6 and the monitor circuit 7 that monitors the data being transmitted on the transmission path 4 by the transmitting/receiving devices 2 and 3 to be tested, and the contents of the communication error are set. A detection circuit 8 detects the timing of occurrence of a communication error in the communication error setting section 9 from the contents monitored by the monitor circuit 7, and a detection circuit 8 detects the timing of occurrence of a communication error from the detection circuit 8. It has a pattern generation circuit 10 that generates a pattern for generating a communication error that is set by the communication error setting section 9, and a transmission circuit 11 that outputs the generated pattern to the transmission line 4.

That is, in FIG. 1, the protocol test system is composed of a transmission line 4, a transmitting station 2 and a receiving station 3 each having a transmitting/receiving device to be tested that is connected to the transmission line 4 and capable of transmitting and receiving data, and a protocol testing device 1. has been done. This protocol test device 1 monitors data sent to a transmission path 4 by a transmitting station 2 having a transmitting/receiving device via a receiver 6 and a monitor circuit 7, and a communication error setting section 9 in which the content of the communication error is set. The detection circuit 8 detects the timing of occurrence of a communication error set in . When the timing of occurrence of this communication error is detected, the pattern generation circuit 10 is driven to generate a communication error pattern corresponding to the content of the communication error in the communication error setting unit 9, and a pattern is generated from there. Ru. This pattern is sent out to the transmission line 4 through the transmission circuit 11 and the dry parameter. Therefore, the data output by the transmitting station 2 having the transmitter/receiver device and the data output by the protocol test device 1 overlap, and the communication error pattern set by the communication error setting section 9 is output on the transmission path 4. At that time, the receiver 6 and the monitor circuit 7 monitor what kind of responses the transmitting station 2 and the receiving station 3, which have transmitting and receiving devices, make.
It monitors the data and analyzes whether it behaves according to the protocol.

Next, we tested the operation of such protocol test equipment at a home A.
An example of application to a tometic digital bus (D2B), which is a control bus for V equipment, will be described with reference to FIGS. 2(a) and 2(b).

FIGS. 2(a) and 2(b) are timing diagrams illustrating an example of the operation of the protocol test apparatus shown in FIG. 1 in a normal state and a parity error occurrence state, respectively.

As shown in FIG. 2(a), during normal D2B communication operation, data (1 byte) 12 is sent from the transmitting station 2, end-off data bit 13 indicating the end of data, data (1 byte) 12, and The end-off data bit 13 and the parity hit 14 for making it odd parity are sent as one unit to the receiving station 3. On the other hand, the receiving station 3 checks the parity bit 14, and if the data is correct, receives 1 byte of data and returns "0" as the acknowledge bit 15 to the transmitting station 2. Furthermore, when transmitting station 2 receives “O” as acknowledge bit 15,
The next data (1 byte>12) is transmitted to the receiving station 3 in the same procedure. Therefore, the data on D2B is as shown in the figure.

In addition, as shown in Figure 2(b), the logic of D2B (bus) is the wired AN of the data output on the transmission path.
This is an example in which an error is generated in parity by using the characteristic of D and using a protocol test device.

First, the protocol test device 1 includes a communication error setting section 9.
, the value of the last bit of the data (1 byte) transmitted by the transmitting station 2 is changed from 1' to 0', and settings are made to generate a parity error.Next, the transmitting station 2
The data output by the receiver 6 and the monitor circuit 7
The data (1 byte) is detected by the detection circuit 8.
Detection is made as to whether or not the final 1 bit of the data is to be output. Furthermore, the pattern generating circuit 10 generates a pattern that outputs "O" at the point where the final 1 bit is output, and the transmitting circuit 11 . The signal is output to the transmission line 4 via a dry parameter. Therefore, even though the transmitting station 2 outputs "1" to the last l bit of the data (1 byte), it becomes "O" on the transmission path 4, and the receiving station 3 outputs "O". Then, since the parity bit "1" transmitted from the transmitting station 2 is not an odd parity, the receiving station 3 returns an acknowledge pid "1" (NAK).
Now, since the acknowledge bit "1" is received, the same data (1 byte) is transmitted again.

In this way, the protocol test device of this embodiment can simultaneously test the transmitting station and the receiving station even if - degree of communication error occurs by superimposing the communication error pattern on the communication data between the transmitting and receiving devices to be tested. It can be carried out.

FIG. 3 is a configuration diagram of communication frames transmitted and received between transmitting and receiving apparatuses for explaining a second embodiment of the present invention.

As shown in FIG. 3, the communication frame includes a source address 16 indicating the address of the transmitting station in the transmitting/receiving device, a receiving address 17 indicating the address of the receiving station in the transmitting/receiving device, and a control indicating the type of communication data. It consists of a code 18 and communication data 19. Similar to the protocol test device shown in FIG. 1, this embodiment uses the source address 16 . When the receiving address 17 matches the address of a specific transmitting/receiving device, a pattern that causes a communication error is placed on the transmission path, thereby interfering with communication from the specific transmitting/receiving device and communication between specific transmitting/receiving devices. This allows for efficient testing in the event that a particular transmitting/receiving device goes down.

The protocol test device of this embodiment described above is configured to superimpose a communication error pattern on the data being communicated between the transmitting and receiving devices and generate a communication error, so it is different from the conventional protocol test device described above. Compared to transmitting communication error frames to the transmitting/receiving device under test in two stages, this method is more efficient and allows testing to be performed in a state closer to the actual occurrence of a communication error.

〔Effect of the invention〕

As explained above, the protocol test device of the present invention generates a communication error by superimposing a communication error pattern on top of the communication data between the transmitting and receiving devices to be tested. This has the advantage that the response of the device can be analyzed at the same time.

In addition, compared to the configuration of conventional protocol test equipment that generates communication errors, the present invention generates communication errors by applying patterns from the outside, so it is easier to test under conditions where actual communication errors occur. It has the effect of being able to

[Brief explanation of drawings]

FIG. 1 is a block diagram of a protocol test device connected to a transmission path showing a first embodiment of the present invention, FIG. 2(a),
(b) is a timing diagram explaining an example of the operation of the protocol test device shown in FIG. 1 in a normal state and in a parity error occurrence state, and FIG. 3 is a communication frame for explaining the second embodiment of the present invention. FIG. 4 is a block diagram of a protocol test device connected to a transmission line showing a conventional example, and FIG. 5 is a schematic diagram for explaining an example of communication between the conventional transmitting station and receiving station in FIG. Figure 6 (a), (b)
) are device connection diagrams for explaining conventional protocol test procedures. 1..., protocol test device, 2... transmitting/receiving device (
transmitting station), 3... transmitting/receiving device (receiving station), 4... transmission line, 5... driver, 6... receiver, 7...
Monitor circuit, 8... Detection circuit, 9... Communication error setting section, 10... Pattern generation circuit, 11... Transmission circuit, 12... Data (1 byte), 13... End of data Bit, 14... Parity bit, 15...
...Acknowledge bit, 16...Sender address,
17... Recipient address, 18... Control code, 1
9...Data.

Claims (1)

[Claims] In a protocol test device that is connected to a transmitting/receiving device via a transmission path and tests whether or not the transmitting/receiving device responds according to the protocol when a communication error occurs, a communication in which the content of the communication error is set. an error setting section, a monitor circuit that monitors data being transmitted from the transmitting/receiving device onto a transmission path, and a detection circuit that detects the timing at which a communication error should occur in the communication error setting section from the content monitored by the monitor circuit. a pattern generation circuit that generates a pattern for generating a communication error in the communication error setting section based on the timing of occurrence of the communication error detected by the detection circuit; and a pattern generation circuit that superimposes the pattern from the pattern generation circuit on the transmission path. A protocol test device comprising: a transmitting circuit that generates a communication error by superimposing the communication error pattern on communication data transmitted and received between transmitting and receiving devices connected to the transmission path.