JPH01258529A - Data bus monitoring device - Google Patents

Abstract

PURPOSE:To attain the monitoring of the action of a data bus without interrupting an action by providing a bus coupling part to detect the data coupled electrically to a serial data bus with non-contact and transmitted to the data bus. CONSTITUTION:A bus coupling part 11 detects the data by the magnetic flux to generate the data current of a serial data bus 12 and sends a detecting signal 14 through a sense amplifier part 16 to a detecting part 17 and a timing generating part 21. The detecting part 17 sends a detecting signal 22 to a waveform shaping part 18. The shaping part 18 receives a timing signal 23 from the generating part 21, waveform-shapes the detecting signal 22 and sends a waveform shaping signal 25 to a bit clock extracting part 27. The extracting part 27 extracts a bit clock signal 29 included in the signal 25 and sends it to a counter part 28. The counter part 28 receives a counting timing signal 32, counts the signal 29 and sends a counting signal 34 to an operation displaying 35. The display part 35 displays the number of the data of a bus 11 and the data load based on the signal 34.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a serial data bus, and more particularly to a data bus monitor device for monitoring data transmitted over this data bus.

[Conventional technology]

With the rapid progress of semiconductor integrated circuits in recent years and the increasing sophistication of microprocessors, the buses that connect components such as arithmetic control units, main memory devices, and input/output interfaces have also become more complex. The main functions of this bus include data transfer, interrupts, direct memory access, and bus resource management. In order to realize such a function, functional requirements such as the function of the bus signal line, data format, data word length transferred in one bus cycle, etc.
It is important to manage electrical requirements such as signal level and timing, as well as mechanical requirements such as signal line length.

Therefore, such a data bus management monitor becomes necessary.

Conventionally, this type of data bus monitoring device has been configured to electrically disconnect the main path line and then connect the bus coupling device thereto in order to obtain a tight coupling with the main data bus. After this connection, the main path line is returned to its original state, the data bus signal is taken out, and thereafter data is received in the same manner as when data is received by a normal bus terminal.

[Problem to be solved by the invention]

As described above, the conventional data bus monitor device has the following problems because it is necessary to temporarily disconnect the pass line in order to extract a signal from the data bus. (1)
(2) When the data bus monitor device is used for winter, the operation of the data bus must be temporarily interrupted. (2) Construction work is required to connect the bus coupling device. (3)
The data receiving circuit becomes large-scale.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a data bus monitor that can monitor the status of a data bus without interrupting the data bus operation while the data bus is in operation, has a simple connection to a bus coupling device, and has a simple processing circuit for the retrieved signals. The goal is to provide equipment.

[Means to solve the problem]

The data bus monitor device of the present invention includes a bus coupling unit that is electrically coupled to a serial data bus via a FATJ3 connector and detects data transmitted through the data bus;
A signal processing section that performs signal processing such as amplification, detection, and waveform shaping on the data detected by this bus coupling section, and a bit clock that extracts and counts a bit clock from the signal output from this signal processing section. The bit clock extraction counter includes an extraction counter and an arithmetic unit that calculates the number of data on the data bus and the data bus load according to the count result of the bit clock extraction counter.

Therefore, when the data bus monitor device according to the present invention is used, the bus coupling section electrically coupled to the serial data bus in a contactless manner detects data on this data bus. This data is subjected to signal processing such as amplification, detection, and waveform shaping in a signal processing section, and then a bit clock is extracted in a bit clock extraction and counting section. Based on this counting result, the arithmetic unit calculates the number of data on the data bus and the data bus load. This makes it possible to monitor the state of the data bus without interrupting the operation of the data bus.

〔Example〕

The present invention will be described in detail below with reference to Examples.

FIG. 1 shows the data bus monitor device of this embodiment.

In the figure, a bus coupling section 11 is constituted by a Hall (effect) element, a current transformer, or the like, and is magnetically coupled to a serial data bus 12 without contact. Then, data is detected by the magnetic flux generated by the data current flowing through the serial data bus 12, and a detection signal 14 is output. This detection signal 14 is manually input to the next signal processing section 15 .

This signal processing 115 includes a sense amplifier section I6, a detection section 17, and a waveform shaping section 18.

When the sense amplifier section 16 receives the detection signal 14, it amplifies it and sends the amplified signal 20 to the detection section 17 and the timing main section 2. Detection section 1 receiving this amplified signal 20
7 detects this and sends a detected signal 22 to the waveform shaping section 18. The waveform shaping section 18 receives the timing signal 23 from the timing generation section 21 that receives the amplified signal 20, takes the timing of the waveform shaping, shapes the waveform signal 22, and outputs the waveform shaping signal 25 to the bit clock extraction and counting section. 2
Send on 6.

The bit clock extraction counting section 26 is composed of a bit clock extraction section 27 and a counter section 28. The bit clock extraction section 27 extracts the bit clock signal 29 included in this waveform shaping signal 25 and sends it to the counter section 28. This counter section 28 is timed by a counting timing signal 32 from a counting timing generator 'B31 that receives a timing signal 23, counts the input bit clock signal 29, and sends a counting signal 34 to an arithmetic display section 35. . The calculation display section 35 calculates and displays the number of data and data load on the serial data bus 11 based on the count signal 34.

FIG. 2 shows the format of data transmitted on the serial data bus 12, and FIG. 3 shows hexadecimal 16-bit data Manchester encoded according to this data format.

In FIG. 2, the data is stored in 1 bit time (l BT
) is made up of 20 units. When each unit is numbered 1.2, ..., 20 in order, the first 3BT1.2.3 indicates a sync pattern used for synchronization,
The next 16B'T4.5, . . . 19 indicate 16-bit data, and the last 1BT20 indicates a parity pit. In Fig. 3, (a) shows the data given in Fig. 2, (b) shows an example of a concrete binary waveform of the data in (a), and (C) shows the data given in Fig. 2. The waveform is expressed in binary numbers of 0 and l according to the Manchester encoding system.

In this Manchester encoded data, "0" indicates that the waveform changes from low (L) level to high (H) level, and "1" indicates that the waveform changes from high (H) level to low (L) level. It can be obtained by In addition to the Manchester code, codes used in such data communications include RZ (Return t
o Zero) code, AM I (Alternat
e Mark Inversion) code, NRZ code, partial response code, etc. Manchester code is characterized by excellent low-frequency cutoff characteristics.

FIGS. 4 to 7 are waveform diagrams showing changes in waveforms at various parts of the device.

In FIG. 4, (a), (b), and (C) respectively indicate the data format, waveform example,
A mantisf code string of this waveform example is shown, and (d) shows an amplified signal 20 after the detection signal 14 detected by the bus coupling section 11 from the serial data path 12 is amplified by the sense amplifier section 16.

In FIG. 5, (a) to (d) show the already explained data format, waveform example, Manchester coded sequence, and amplified signal 20, and (e) shows the amplified signal 20 detected by the detection section 17. 2 shows a detected signal 22 obtained by

Similarly, FIG. 6 shows a waveform-shaped signal 25 (
(f)) of the figure is shown. Figures (a) to (e) have already been explained.

FIG. 7 shows a bit clock signal 29 obtained by extracting only the bit clock from the waveform shaping signal 25 in FIG.
f)). The other waveforms ((a) to (') in the figure) have already been explained.

As can be seen from this bit clock signal 29, from l word data, 18
Clocks can be extracted.

Therefore, the number of data transmitted on the serial data bus 12 is immediately known from the count signal 34 obtained by counting this bit clock signal 29 by the counter section 28, and this is displayed on the calculation display section 35. be done. Further, based on this count signal 34, the calculation display unit 35 calculates and displays the ratio between the theoretical value of the number of data transfer words and the above count value.

From this the load of the serial data bus 12 is obtained.

〔Effect of the invention〕

As described above, the data bus monitor device of the present invention detects data on the data bus using the bus coupling device that is electrically coupled to the serial data path without contact, and after amplifying, detecting, and waveform-shaping the data, , the bit clock included in the detected data is extracted by the bit clock extractor,
By calculating the number of data on the data bus and the data bus load using the arithmetic unit based on this extracted bit clock signal, the state of the data bus can be monitored without interrupting the operation of the data bus. There is. Further, according to the present invention, the bus coupling device includes:
It can be easily connected to the pass line without cutting it, and the circuits necessary for monitoring the number of data such as the signal processing section can be easily configured, resulting in a significant cost reduction.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the data bus monitor device according to the present invention, FIG. 2 is a diagram showing the format of data transmitted on the data bus, and FIG. 3 is a block diagram showing the format of data transmitted on the data bus. Figure 4 shows the output waveform of the sense amplifier section, Figure 5 shows the detected waveform of the detection section, and Figure 6 shows the signal waveform after waveform shaping in the waveform shaping section. FIG. 7 is a diagram showing a bit clock extracted from the signal waveform of FIG. 6. 11...Bus coupling section, 12...
・Serial data bus, 15...Signal processing unit, 2G...Bit clock extraction counting unit, 35...
...Calculation display section. Representative of NEC Co., Ltd.

Claims (1)

[Claims] A bus coupling unit that is electrically coupled to a serial data bus without contact and detects data transmitted through the data bus; and a bus coupling unit that amplifies the data detected by the bus coupling unit. , a signal processing section that performs processing such as detection and waveform shaping, a bit clock extraction counting section that extracts and counts bit clocks from the signal output from this signal processing section, and a 1. A data bus monitor device comprising a display unit for counting and displaying the number of data on a data bus and the data bus load.