JPS59100651A - Hand shake transmitting system by loop bus - Google Patents

Abstract

PURPOSE:To reduce the number of connecting points and repeaters by constituting a transmitted signal frame so as to include the time area of a command signal from a talker and the time area of a response signal from a listner to a talker. CONSTITUTION:A talker station STS1 and listner stations STS2-S4 are connected to a loop bus line L and a device E is connected to each ST by a branched bus line L'. A signal frame transmitted from the talker STS1 is returned to the talker STS1 through the listners STS2-S4. When a frame signal is received, a control signal NTC and a DAV representing the data transmission of a new cycle are separated from an output Sout and the data received by the ST is extracted from the Dout. In transmitting data from the ST, the switching circuit SW is changed over to a contact 3 in the timing of the data area, and the data is inserted from an input Din. The SW is changed over to a contact 2 in the timing of the control signals NRFD, NDSC and the logical sum 0 between the control signal in the frame signal and the control signal of the own ST is transmitted to the line L.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a data transmission system between information processing devices or between a main device and a slave device of information processing devices. especially,
The present invention relates to a data transmission method for transmitting and receiving data via a Hass line using a handshake method.

The handshake method is a method in which a means for transmitting control signals is installed along with the path line that transmits data, and a command signal is transmitted from a station that is a talker that transmits data to a station that is a listener that receives data. From this command signal device, the listener station sends and receives data to and from the path line while returning a response signal to the talker station according to its state. The control signal transmission path can be provided in a space-division manner or a time-division manner with respect to the data transmission line.

The handshake method is widely used because it is an excellent method that allows devices with different response speeds to be connected to a common transmission path and ensures extremely reliable data transmission and reception. This handshake method is also implemented in a system in which many stations are branch-connected to a single path line, with one station acting as the source and multiple other stations acting as listeners. There is. In this case, the control signal transmission path is made, for example, a wiped-OR connection at each station.

However, in the conventional system, each station is connected by branching, so as the number of stations to be connected increases and the distance to those stations increases, ■ Connection points and repeaters 1) the signal load increases; 2) the delay in the transmission path increases and the communication efficiency decreases.

The present invention, without losing the advantages of the handshake method,
To solve the above-mentioned drawbacks, and to provide a system that allows the number of connection points and repeaters to be reduced, and that allows a Hassline to be constructed economically even if the stations are located in the same geographical location. The purpose is to

In the present invention, each station is connected in a loop by a lotus line, and on this loop-connected lotus line,
The configuration is such that a signal frame transmitted from a station serving as a talker, passes through each station serving as a listener, and returns to the station serving as one source is relayed. This signal frame is configured to include a time domain of a command signal transmitted from a station serving as a talker to a station serving as a listener, and a time domain of a response signal transmitted from a station serving as a listener to a station serving as a talker. The station that becomes a listener writes and transmits the logical product or logical sum of the received response signal and the logical value of its own station's response signal in the time domain of the response signal, and the talker station The method is characterized in that it is configured to control the next transmission step based on the received response signal.

This will be explained in more detail using the drawings.

FIG. 1 is a time chart showing the procedure of data transmission using the conventional handshake method. DATA indicates the timing of data sent on the path line from the station serving as the talker. Signal line DAV (DAT＾ν＾LI
In D), a command signal is sent from the talker station to the listener station. A word line NRFD
(NOT RADY FORDAT8) and NII
For AC (DATA NOT ACT), a response signal is transmitted from a station serving as a listener to a station serving as a talker. The station that becomes the talker is the signal line DAV
When the signal line NRFD is set to logic 'IJ', the listener station responds by setting the signal line NRFD to logic '1'. At the talker station that receives this, if the data sent to the Hassline at that time is valid,
Set the signal line DAV to logic "1". The listener station takes in the data on the path line and sends it to the signal line NDA.
A logic "1" is sent to C. The talker station that receives this sends the logic 'IJ' to the signal line DAV and moves on to the next cycle.

When a plurality of listener stations are connected to this transmission line, each signal line is connected, for example, in a wiped-OR manner.

In this way, in the handshake method, data is transmitted while transmitting and receiving control signals in one cycle. As the number of stations connected to a transmission line increases, the load and delay inevitably increase.

FIG. 2 is a station connection diagram according to an embodiment of the present invention. 4 (flit stations 81 to S2 are connected in a loop by a lotus line L. Each station 81
.about.S4 are connected to devices E, either alone or by another branch-like path line L'. Here, the stations 81 to S4 are configured to mutually transmit and receive data using a handshake method.

That is, if Sl now becomes a talker and another station becomes a listener, the path line L from station S1
A frame signal having a frame structure as illustrated in FIG. 3 is transmitted. This frame signal includes, in addition to the frame identification code F and the data area DATA, an NTC (NEW TIIANSM) indicating a new cycle of data transmission.
ISSION CYCLE) code and DAV (D
ATA VALID) code is inserted between the frame identification code and the data area, and after the data area, the NRFD
Areas for the (NOT READY FORDATA) code and the N0AC (NOTDATA ACT) code are arranged.

FIG. 4 is a block diagram of main parts of a station according to an embodiment of the present invention. Signal 1 of pass line L is received by receiving circuit RX
The digital signal is amplified and reproduced. The output of the receiving circuit RX is connected to the first contact 1 of the switching circuit needle.

The output of the receiving circuit RX is branched and connected to one input of the OR circuit 0.

A control signal input Sin is connected to the other input of this OR circuit O. The output of the OR circuit O is connected to the second contact 2 of the switching circuit SH. The output of the receiving circuit RX is further branched and connected to the data output Dout. A data input Din is connected to the third contact 3 of the switching circuit SH. The output of the receiving circuit RX is guided to the control circuit TC, and this control circuit T
A control signal output 5out is sent to the output of C. Further, the switching circuit SW is controlled by the output of the control circuit TC. The output of the switching circuit S- is transmitted from the transmitting circuit TX to the lotus line L of the next section.

In the device configured as shown in Fig. 4, the switching circuit S
W is connected to the first contact 1. When the frame signal explained in FIG. 3 is received, the control signals NTC and DA
V is separated and output to the output Sout.

If the data of this frame signal is received at that station, it is retrieved from the data output pout. When transmitting data to this data area at this station, the switching circuit S- is switched to the third contact 3 at the timing of the data area, and data is inserted from the data input input Din. At the timing of the control signal following the data area, the switching circuit SW is switched to the second contact 2, and the output of the OR circuit 0 is transmitted to the pass line L. The OR circuit 0 outputs the logical sum of the logical value of the control signal in the received frame signal and the logical value of the control signal of the own station.

In this way, each station 82 to S shown in FIG.
When the frame signal returns to station S1, one cycle of data transmission using the handshake method has been executed.

Each station distributes the necessary data to the devices E connected to each station.

The present invention is suitable for implementation in an optical communication system using an optical fiber as a transmission path.

In the above example, the types of control signals for handshake are 4 (1!
Although an example in which the control signal is a control signal has been described, the present invention is not limited to this type of control signal, and the present invention can be implemented with various types of control signals.

As explained above, according to the present invention, data can be reliably transmitted without losing the advantages of the handshake method, and the number of connection points and repeaters can be reduced, so that stations can Even in the case of geographical placement, the distance of the path line is shorter than in the case of branch connections, making it possible to construct the entire system economically.

[Brief explanation of the drawing]

FIG. 1 is a time chart illustrating handshake type communication control operation. FIG. 2 is a diagram illustrating a transmission line configuration according to an embodiment of the present invention. FIG. 3 is a configuration diagram of the frame signal. FIG. 4 is a diagram showing the main part of the station according to the embodiment of the present invention. 81~S2...Station, E...Installation fW, L.
...Loop-shaped pass line. 1 Ki 1 Claw 2 ■

Claims (1)

[Claims] (1) In a system in which one or more talker stations and two or more listener stations are connected by a path line, data is transmitted from the talker station to the listener station by a handshake method, Each of the above stations is connected in a loop by a path line, and on this loop-connected path line, a signal frame is transmitted from the talker station and returns to the talker station via each listener station. This signal frame includes a command signal transmitted from the talker station to the listener station, and a response signal transmitted from the listener station to the talker station. The listener station calculates the AND or OR value of the received response signal and its own station's response signal in the time domain of the response signal. 1. A handshake transmission system using a loop bus, characterized in that the station that writes and transmits data to the above-mentioned station is configured to control the next transmission step based on a received response signal.