JPS60236542A - Bus connection control system - Google Patents

Abstract

PURPOSE:To reduce connection/release processing to the bus for a slave device by providing a signal bus for connection of all master and slave devices in addition to a bus, transmitting a signal designating a slave device to be connected to the bus to the signal bus by the master device and connecting the designated slave device to the bus. CONSTITUTION:A control part CTL' within a master device ME that starts communication actuates a connection control part CNC to send the address of a slave device SEi' and to receive communication to a signal bus SB. At connection parts CN1-CNn, decoders DC1-DCn receive the addresses delivered from the bus SB, and only the connection part CNi having coincidence with the address given to the own device SEi' sets both the transmission and reception part R' and D under a conduction state respectively. As a result, only the device SEi' is connected to an information bus IB via the parts R' and D within the part CNi to attain communication with the device ME. The device ME which is through with communication with the devices SEi' stops the transmisson of the address of the device SEi' to the bus SB.

Description

DETAILED DESCRIPTION OF THE INVENTION ta+ Technical Field of the Invention The present invention relates to a bus-type communication system, and more particularly to a bus connection control method that can reduce connection release processing of slave devices to the bus.

(b) Background of the technology One main device and a plurality of slave devices are connected, for example, by a loop bus, and under the control of the main device, the main device and one or more slave devices are connected. Communication systems that transmit and receive data via buses are widely used.

(C) Prior Art and Problems FIG. 1 is a diagram showing an example of a conventional communication system of this type. In FIG. 1, one main device ME and n slave devices SEl to SEn are connected in a loop by an information bus IB. Each main device ME and slave devices SEl to SEn have a transmitter that transmits data to the information bus IB, a receiver R that receives data arriving from the information bus IB, and a control and control unit for the transmitter and receiver R. It is composed of a control unit CTL that performs data analysis processing.

The main device ME and each of the machines SE1 to SEn, which are in a non-communication state, set the receiving section R to a conductive state and the transmitting section to a blocked state, and set the transmitting section to a conductive state for the first time when transmitting data. Control unit C in the main device ME that starts communication
After connecting the transmitter to the information bus IB, the TL starts the command transmitter CMS and sends the address assigned to the slave device SEi (+ is one of 1 to n) to be communicated via the transmitter. Send information to Hass IB. Each of the Western devices SEI to SEn receives the address transmitted from the main device ME via the information bus IB via the receiving section R, and receives the address transmitted from the main device ME via the information bus IB.
The slave device SEi, which has been analyzed by the command receiving section CMR in the TL and matches the address given to its own device, sets the transmitting section to a conductive state and exchanges data with the main device ME via the information bus IB. Send and receive. When the communication with the slave device SEi is completed, the command sending unit CMS of the main device ME instructs the command receiving unit CMH of the slave device SEi to set the transmitting unit to the blocked state, and then performs the next step in the same process as described above. starts communication with slave device sEj (j is any one from 1 to n).

As is clear from the above explanation, in a conventional communication system, each of the Western devices SEI to SEn analyzes the address transmitted from the main device ME via the information bus IB to obtain information about the transmitting section of its own device. It connects to the bus IB and also controls the transmitting section to the information bus IB according to instructions transmitted from the main device ME.
Each slave device S is executing the process of releasing it from B, and each slave device S
This has the disadvantage that the processing of IF, l to SEn becomes complicated and the load increases.

ld) Object of the Invention An object of the present invention is to eliminate the drawbacks of the conventional communication systems as described above and to realize a means that can reduce the connection release process of a slave device to a lotus as much as possible.

(81 Structure of the Invention This object is to connect a main device and a plurality of slave devices by a single bus, and to connect the main device and the plurality of slave devices via the bus under the control of the main device. In the communication system, a signal bus is provided that connects all the main devices and slave devices independently of the bus, and the main device sends a signal specifying a slave device connected to the bus to the signal bus. This is accomplished by sending a signal to the bus and connecting the slave device designated by the signal to the bus.

That is, according to the present invention, the process of releasing the connection of each slave device to the bus is all performed centrally by the main device, so the process of releasing the connection of each slave device to the bus is completely unnecessary.

(fl　Embodiments of the invention An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a diagram showing a bus connection control method according to an embodiment of the present invention. Note that the same reference numerals refer to the same objects throughout the plan. In FIG. 2, the control unit CT in the main device ME
L' is provided with a connection control unit CNC instead of the command transmission unit CMS, and each Western device SEI' to SEn
' are connected to the information bus IB via the connections CNI to CNn, respectively, and further connected to the main device ME and each connection CNI.
The signal bus SB connecting CNn to CNn is the information bus IB.
It is provided in addition to. Each connection part CNI to CNn is
They each include a receiving section R' and a transmitting section transferred from the corresponding slave devices SEI' to SEn", and decoders DCI to DCn, respectively. Note that in the connecting sections CNI to CNn which are in a non-communication state, Not only the transmitter but also the receiver R.

is also set to a blocked state. In FIG. 2, the control unit CTL' in the main device ME that starts communication activates the connection control unit CNC and causes the address of the slave device SEi' to be communicated to be sent to the signal bus SB. In each connection part CNI to CNn, decoder DCI to DC
n receives the address arriving from the signal bus SB, and only the connection part CNi that matches the address given to the own axis device 5Ei1 brings the reception part R° and the transmission part in the own connection part CNi into a conductive state. Set to . As a result, slave device SEi'
Only one of them is connected to the information bus IB via the receiving section R1 and the transmitting section in the corresponding connection section CNi, and is capable of communicating with the main device ME. After completing the communication with the slave device SEi, the main device ME stops sending the address of the Western clothing WsEi' to the signal bus SB. As a result, the decoder DCi sets the receiving section R° and the transmitting section in the self-axis device SEi' to a blocking state, and disconnects the corresponding slave device SEi' from the information lot IB. From now on, the main device ME will communicate with the Western-style fi
The address of sEj' is sent to the signal hash SH, and communication is performed with the slave device sEj' in the same process as described above.

As is clear from the above description, according to this embodiment, each of the connection units CNI to CNn is controlled by the connection control unit CNC in the main device ME, and the corresponding slave devices S'EI' to SEn Since ' is released from the information bus IB, there is no need to perform connection release processing for the information bus IB from each of the Western devices SEI° to SEn'.

It should be noted that FIG. 2 is only one embodiment of the present invention, and for example, the configuration of the main device ME and each connection section CNI to CNn,
Furthermore, the shape of the information bus IB is not limited to that shown in the drawings, and many other modifications may be considered, but the effects of the present invention will not change in any case.

(gl) Effects of the Invention According to the present invention, there is no need to perform connection release processing for the slave device to the bus, and the load on the slave device is significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a conventional communication system, and FIG. 2 is a diagram showing a lotus connection control system according to an embodiment of the present invention. In the figure, CMR is a command reception section, CMS is a command transmission section, CNI to CNn are connection sections, CNC is a connection control section, CTL and CTL' are control sections, D is a transmission section, DCI to DCn are decoders, and IB is the information bus, ME
is the main device, R and Ro are the receivers, SB is the signal lot, S
D indicates a signal transmitting section, SEl to SEn are slave devices, and SR indicates a signal receiving section.

Claims (1)

[Claims] A communication system in which a main device and a plurality of slave devices are connected via a single bus, and the main device and/or the plurality of slave devices communicate via the bus under the control of the main device, A signal bus is provided to connect all the master devices and slave devices independently of the bus, and the master device sends a signal to the signal bus specifying the slave device to be connected to the bus, and the bus is designated by the signal. A bus connection control system characterized in that a slave device is connected to the bus.