JPH05227169A - Bi-directional bus data transfer system - Google Patents

Abstract

PURPOSE:To reduce the signal processing by deliberately superimposing output signals on one signal line and allowing signal processing sections to detect a bus fight to control the I/O direction. CONSTITUTION:In outputting data from a signal processing section 1, the section 1 outputs a signal generating a bus fight to a signal line 7 on purpose. Signal processing sections 2 and 3 detects the bus fight at bi-directional buffers 5 and 6 to switch them to an input mode. The section 1 confirms the switching of input mode based on no generation of bus fight, transmitting data. Then, in outputting data from the section 2, the section 2 transmits the signal generating a bus fight to the signal line 7 on purpose and the sections 1 and 3 detects a bus fight by means of bi-directional buffers 4 and 6. Thus, the buffers 4 and 6 are switched to an input mode and the signal processing section 2 confirms the switching to transmit data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bidirectional bus data transmission system used in a data transmission system for transmitting and receiving data through a bidirectional bus.

[0002]

2. Description of the Related Art FIG. 2 shows the configuration of a conventional bidirectional bus data transmission system.

In FIG. 2, a bidirectional buffer 11 in the signal processing unit 8 and a bidirectional buffer 12 in the signal processing unit 9 are shown.
And the bidirectional buffer 13 in the signal processing unit 10 are connected to the signal line 14 to form a bidirectional bus line.

The control signal S15 of the signal processing unit 8 is input to the signal processing unit 9 as a control signal in the input / output direction, and the control signal S16 of the signal processing unit 8 is input to the signal processing unit 10 as a control signal in the input / output direction. Is entered.

Next, the operation of this configuration will be described.

When outputting data from the signal processing unit 8,
The bidirectional buffer 11 of the signal processing unit 8 is set to the output mode. Further, the bidirectional buffer 12 of the signal processing unit 9 is set to the input mode by the control signal S15. Further, the bidirectional buffer 13 of the signal processing unit 10 is set to the input mode by the control signal S16, and then the data is output.

When outputting data from the signal processing unit 9,
The bidirectional buffer 11 of the signal processing unit 8 is set to the input mode, and the bidirectional buffer 1 of the signal processing unit 9 is set by the control signal S15.
Set 2 to output mode. Further, the bidirectional buffer 13 of the signal processing unit 10 is set to the input mode by the control signal S16 to output the data.

Similarly, when outputting data from the signal processing unit 10, the signal processing unit 8 uses the bidirectional buffer 11 and the control signals S15 and S16 to connect all the bidirectional buffers 11, 12, and 13 to the signal line 14. Output data after setting to input mode.

[0009]

As described above, in the conventional bidirectional bus data transmission system, the bidirectional buffers 11 and 1 are used.
In order to control the input / output modes of 2 and 13, input / output control signals S15 and S16 are required as many as the number of signal processing units 8, 9 and 10 connected on the bidirectional bus.

Further, there is a drawback that even if a data error occurs due to a so-called bus fight, a plurality of output signals are intentionally superimposed on the bidirectional bus due to an error in the control signal, but it cannot be detected.

The present invention solves such a problem, and can reduce the scale of signal processing by eliminating the need for control signals in the input / output direction, which are required for the number of signal processing units conventionally connected to the bidirectional bus. Another object of the present invention is to provide a bidirectional bus data transmission method in which the occurrence of a data error due to a bus fight is prevented and the efficiency of data processing is improved.

[0012]

In order to achieve this object, the bidirectional bus data transmission system of the present invention connects the bidirectional buffers of a plurality of signal processing units on one signal line, and In a two-way bus data communication system in which data communication is performed by controlling the input / output direction by at least one signal processing unit in a plurality of signal processing units, a bidirectional buffer equipped with a bus fight detection circuit is provided in the bidirectional buffer to provide one signal. It is characterized in that a plurality of output signals are intentionally superimposed on a line, and a plurality of signal processing units detect a bus fight and independently control the input / output direction.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the bidirectional bus data transmission system of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of the embodiment.

In FIG. 1, a bidirectional buffer 4 provided with a so-called bus fight detection circuit for intentionally superposing a plurality of output signals on the bi-directional bus in the signal processing unit 1, that is, a so-called bus fight detection circuit, and a signal processing unit. The bidirectional buffer 5 including the bus fight detection circuit 2 and the bidirectional buffer 6 including the bus fight detection circuit of the signal processing unit 3 are connected by the signal line 7 to form a bidirectional bus line. Next, the operation of this configuration will be described.

When outputting data from the signal processing unit 1,
First, the signal processing unit 1 intentionally outputs a signal that causes a bus fight to the signal line 7.

The signal processing units 2 and 3 are bidirectional buffers 5 and 6.
Detects the bus fight and switches the bidirectional buffers 5 and 6 to the input mode.

In the signal processing unit 1, the bidirectional buffers 5 and 6 of the signal processing units 2 and 3 confirm the switching of the input mode by the non-occurrence of the bus fight and transmit the data.

Next, when outputting data from the signal processing unit 2, first, the signal processing unit 2 intentionally outputs a signal for causing a bus fight to the signal line 7. Signal processing unit 1, 3
Detects a bus fight by the bidirectional buffers 4 and 6 and switches the bidirectional buffers 4 and 6 to the input mode.

In the signal processing unit 2, the bidirectional buffers 4 and 6 confirm the switching of the input mode by the non-occurrence of the bus fight, and send the data.

Similarly, when outputting data from the signal processing unit 3, a bus fight is intentionally generated, the bidirectional buffers 4 and 5 of the signal processing units 1 and 2 are switched to the input mode, and the data is transmitted.

[0022]

As is apparent from the above description, in the bidirectional bus data transmission system of the present invention, the bidirectional buffer is provided with the bidirectional buffer equipped with the bus fight detection circuit, and the plural bidirectional buffers are intentionally provided on one signal line. The number of signal processing units connected to the conventional bidirectional bus is increased because a bus fight that superimposes the output signal is generated and multiple signal processing units detect the bus fight and can control the input / output direction independently. The control signal in the input / output direction, which is required only, is no longer necessary, and the effect is that the signal processing scale can be reduced.

Further, since the bus fight detection circuit is provided, the data error due to the bus fight does not occur, and the efficiency of data processing is improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration in an embodiment of a bidirectional bus data transmission system of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional bidirectional bus data transmission system.

[Explanation of symbols]

 1, 2, 3 Signal processing unit 4, 5, 6 Bidirectional buffer 7 Signal line

Claims (1)

[Claims] 1. Data is connected by connecting bidirectional buffers of a plurality of signal processing units on one signal line, and controlling the input / output direction of the bidirectional buffer by at least one signal processing unit in the plurality of signal processing units. In a two-way bus data communication method for performing communication, a bidirectional buffer including a bus fight detection circuit is provided in the bidirectional buffer, and a plurality of output signals are intentionally superimposed on the one signal line,
A bidirectional bus data transmission method, wherein the plurality of signal processing units detect a bus fight and independently control an input / output direction.