JPH0568041A - Communication control system - Google Patents

Abstract

PURPOSE:To acquire a light of communication independently of the sequence of tokens in a token system data bus. CONSTITUTION:Each terminal equipment sets an urgent interrupt slot in non- transmission state by giving a prescribed time space till a succeeding token number is outputted to a data bus 1 after the end of data transfer. A terminal equipment requiring urgent consecutive transmission of data outputs its own token number from a token transmitter 21 when a BTO detector 24 detects a non-transmission state. When a token receiver 23 receives no token number of other terminal equipment, a data transmission reception control section 30 outputs data while regarding a token of a data bus to be acquired.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication control system, and more particularly to a bus system communication control system for transferring data using the token system.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 2, this type of communication control system has a host CPU 40, a terminal A41, and a terminal B4.
2 and each node of the terminal C43 are assigned consecutive allocation token numbers 100 to 103.

Each node acquires the data transmission right in the order of the assigned token numbers.

In the conventional example of FIG. 3, [host CPU 40] → [terminal A41] → [terminal B4] in the order of assigned token numbers.
2] → [Terminal C43] are repeated so that each device cyclically acquires the data transmission right at the same ratio and executes the data transfer.

[0005]

In this conventional communication control method, as shown in FIG. 3, token numbers are randomly assigned and each node obtains the data transmission right at the same rate, so that a specific toad is It is not possible to obtain the transmission right at a rate higher than that of the node.

Therefore, there has been a problem that the transmission right cannot be obtained when data needs to be frequently transferred or when urgent data is desired to be transmitted.

An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a communication control system which allows a specific node to be given a transmission right larger than those of other nodes and enables frequent data transfer and emergency data transmission. To provide.

[0008]

According to the method of the present invention, in a communication control method of a bus system for controlling data transfer using a token method, a non-transmission state is provided between data transfer and token transmission. It has a configuration in which a specific node that needs to perform data transmission frequently or a node that needs emergency data transmission can forcibly obtain the communication control right.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

The communication control system of the embodiment shown in FIG. 1 has a data bus 1, a bus interface unit 10 for interfacing with the data bus 1, a token control unit 20 for controlling tokens, a data bus 1 and a CPU. / A data transmission / reception control unit 30 that transmits / receives data to / from the terminal device.

The token control unit 20 includes a token transmitter 21 for transmitting a token, an output controller 22 for controlling the timing of token transmission, a token receiver 23 for processing a token number received from the data bus 1, and a data receiver. The BTO detector 24 detects a transmission state (Bus Time Out: BTO).

In the token type data bus, a token number is acquired at the time of initialization, data is sequentially transmitted from 0, if necessary, and finally the next token number is output to the data bus.

In this embodiment, when the token received by the token receiver 23 matches the token designated by the token receiver 23, the data transmission / reception control unit 30 sends data to the data bus 1 via the bus interface unit 10. Output.

After the output of data is completed, the output controller 2
According to the instruction of 2, the token transmitter 21 outputs the next token number to the data bus 1 after T1 time. Therefore T1
Time becomes a non-transmission state, and this is used as an interrupt slot. This state is shown in the normal state of FIG.

When transmission data is generated in a device having a high priority, data transfer is performed using the emergency interrupt slot of this time T1 by the following procedure. Until another device outputs the next token number after data transfer (T1
Time), the data bus 1 is in a non-transmission state.

BTO detector 2 of the device with transmitted data
4 detects this non-transmission state and notifies the output controller 22 of it.

The output controller 22 outputs its own token number from the token transmitter 21 to the data bus 1 via the bus interface unit 10.

In this way, the transmission right of the data bus 1 can be acquired and necessary data can be continuously transmitted.
After the data transfer is completed, the next token number is assigned to the data bus 1
Other devices can also sequentially acquire the transmission right by outputting to. This state is shown at the time of emergency data transmission in FIG.

[0020]

As described above, according to the present invention, in the communication control method of the bus system for controlling the data transfer using the token method, no transmission is performed between the data transfer and the output of the next token number. By setting the status and using this time as the emergency interrupt slot, the device that needs data transfer urgently can acquire the transmission right to send data to the data bus urgently and preferentially transfer data. It has the effect of being able to.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a communication control system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a transfer timing on a data bus in the embodiment of FIG.

FIG. 3 is a block diagram showing a configuration of a conventional communication control system.

[Explanation of symbols]

 1 Data Bus 10 Bus Interface Unit 20 Token Control Unit 21 Token Transmitter 22 Output Controller 23 Token Receiver 24 BTO Detector 30 Data Transmission / Reception Control Unit 40 Host CPU 41 Terminal A 42 Terminal B 43 Terminal C 100-103 Allocation Token

Claims (1)

[Claims] 1. A communication control method of a bus system for controlling data transfer using a token method, wherein a non-transmission state is provided between data transfer and token transmission, and data transmission must be frequently performed. A communication control method characterized in that the above node or a node requiring emergency data transmission is forced to obtain communication control.