JPS59158160A - Data transmitter - Google Patents

Abstract

PURPOSE:To prevent data omission and double reception of data by providing state display for requesting resending to a transmitting origin without receiving a frame of multiple address communication once the frame of multiple address communication is received in each transmitter when said frame is transferred. CONSTITUTION:When a frame is transferred to all data transmitters, the espective transmitters generate signals on receivable signal lines 303 and 304 by signals supplied from frame detecting circuits 101 through signal lines 202-204, actuating frame receiving circuits 102. When, however, the receiving buffer in some frome receiving circuit 104 is busy, an FF123 is set. If a frame addressed to this station except multiple address communication is received in said period, a frame receiving signal line 203 turns on and an all-station address signal line 204 turns off. When a target frame addressed to all the stations is supplied, an all-station address receive signal line 204 turns on and then a signal is generated on an FCSOk signal line 205. When, however, the buffer busy signal line 205 of a frame receiving circuit 102 turns on, a signal is generated on a signal line 307 and a busy transmission request flip-flip 125 is set.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a data transfer device in a loop data transmission system.

BACKGROUND OF THE INVENTION Conventionally, broadcast communications in looped data systems of this type include means for sending data unconditionally. For this reason, when many loop-shaped transmission paths are used, or when data is sent from each data transmission device to a specific data transmission device in a concentrated manner, the buffer of the data transmission device on the receiving side becomes full. And they may not receive it. For this reason, there are cases where data is missing, and to prevent data from missing,
In order to manage response frames, all data transmission devices connected in a loop must return response frames to the transmitting data transmission device almost simultaneously. For this reason,
The disadvantage is that the number of response frame receiving circuits corresponding to the number of data transmission devices connected in a loop is required, and the amount of hardware increases.

OBJECTS OF THE INVENTION The object of the present invention is to solve the above-mentioned drawbacks, and to provide a data transmission system in which data transmission systems transfer pitton-to-can frames through a loop-shaped transmission path between a plurality of data transmission devices. In the apparatus, a storage means for storing frames of the received circular communication, and when the frame of the circular communication is supplied before a transfer completion report of the circular communication is received and the conditions of the content stored in the storage means are satisfied; It is equipped with means for notifying the sender of a retransmission request, and means for notifying the sender of the retransmission request when the frame of the broadcast communication cannot be received normally.

Next, one embodiment of the present invention will be described in detail with reference to all the drawings. Referring to FIG. 1 in its entirety, the system to which the present invention is applied is comprised of data transmission devices 1-4 and transmission lines 11-14.

Referring to FIG. 2, one embodiment of the present invention includes a photoelectric conversion circuit 30, a clock line 51 for transmitting a clock signal after photoelectric conversion, and a data line 52 for transmitting data after photoelectric conversion.
, a transmission line control circuit 32, a clock line 54 that sends a clock to the transmission line, and a data line 55 that sends data to the transmission line.
, a processor 33 that performs microprogram control, a data bus 81, a line group 83 that transmits control signals that control the transmission line control circuit 32, a signal line 84 used in the transmission line control circuit 32, and a write signal line 82. It is composed of

Referring to FIG. 3, the transmission path control circuit 32 in FIG. a frame transmitting circuit 103 for sending to the Internet, a shift register 111 for serial-to-parallel conversion, a command decoder 112, a reception prohibition reset request flip-flop 122, a busy flip-flop 123, a reception prohibition flip-flop 124,
a busy transmission element flip-flop 125, a flip-flop 129 that temporarily holds transmission data, a flip-flop 130 that indicates that a busy frame is being received, a destination address line 71 that is output from the frame reception circuit 102 and used to return a response; A timing signal line 201 that transmits a timing signal for decoding a command, a reception signal line 203 that shows a frame reception signal indicating that a frame addressed to a station or all stations is being received, and a reception signal line 203 that transmits a reception signal addressed to all stations indicating that a frame addressed to all stations is being received. A signal line 204, a signal line 205 that transmits a buffer busy signal indicating that the reception buffer is full and cannot receive data, a data bus 207 that transmits serial data output from the frame transmission circuit 103, and a frame transmission signal in response to the end of buffer busy transmission. A signal line 208 that transmits the transmission end signal generated from the transmission circuit 103, a reset of the flip-flop 123, and a
Signal line 301 for transmitting all control signals for setting 4
, a signal line 302 for transmitting a reception prohibition reset signal for resetting the reception prohibition flip-flop 124, a signal line for transmitting reception enable signals 303 and 304'e for activating the frame reception circuit 102, and a signal line for transmitting the busy transmission request flip-flop 125. , signal lines 305, 306, 307 and 308 for transmitting signals for decoding, decoder 1
Output signal lines 502 and 50 carrying 12 output signals
3. Signal line 601 for transmitting all signals sent to flip-flop 123, NAND circuit 401, AND circuit 402
, a driver 403, and a receiver 404.

Referring to FIG. 4, the frame applied to the present invention has a flag pattern "'01111110" F1 destination address DA, source address SA, control information C, data information processing, and frame check sequence. It consists of a cyclic redundancy check pit FC8 for checking whether the data has been transferred correctly. Note that the control information may be omitted from the frame.

Next, the operation of one embodiment of the present invention will be explained in detail.

Now, when a frame addressed to all stations is transferred from data transmission device 4 to all data transmission devices, each data transmission device
The light is converted into an electrical signal in the photoelectric conversion circuit 30 shown in the figure. The converted signal is sent to the clock line 51 and data line 5.
2 is applied to the frame detection circuit 101 and shift register 111 in FIG. 3 via an information frame. The frame detection circuit 101 detects the timing signal line 20 when the control information portion C shown in FIG. 4 is applied to the shift register 111.
A signal is generated at 1. However, since the transmitted frame is normal data, no signals are generated on signal lines 501 and 502. At the same time, signals provided from the frame detection circuit 101 via signal lines 202, 203, and 204 allow receivable signal lines 303 and 3.
04 is generated and the frame receiving circuit 102 is activated.

However, if the receiving buffer in the frame receiving circuit 104 is busy, no frame is stored in the receiving buffer, and a signal is generated on the signal line 601, so that the shift flip-flop 123 is set. The flip-flop 123 is set, and during this period, if all frames addressed to the own station, which are not broadcast communications, are received, the frame reception signal line 20
3, a signal is generated on the signal line 306.

In response to the generation of this signal, busy transmission request flip-flop 125 is turned on, activating frame detection circuit 103. As a result, the busy frame is sent out to the signal line 207 with the frame configuration shown in FIG.

This circuit 30 converts electricity into light, which goes out onto a transmission path and returns to the source.

In response to this reply, a busy transmission end signal 208 is generated and flip-flop 125 is set. At this time, simultaneously with the operation of generating the busy frame, the receivable signal lines 303 and 304 are turned off. Therefore, the frame receiving circuit 102 is not activated, and the busy flip-flop knob 123 remains in the on state without being reset.

Thereafter, when the intended frame addressed to all stations is given from the data transmission device 4, a signal is generated on the all station reception signal line 202. However, if the buffer busy signal line 205 of the frame receiving circuit 102 is in the on state, the signal line 3
A signal is generated at 07, the busy transmission request flip-flop 125 is set, and the same operation as the busy frame transmission described above is performed. 2 At this time, the frame cannot be received because the buffer is busy. On the other hand, in response to the reception of the buffer busy frame, the data transmission device 4 of the transmitting station learns that one of the data transmission devices connected to the loop transmission path is buffer busy, and sends the same frame addressed to all stations again. Send. In response to the supply of frames addressed to all stations, the receivable signals a303 and 304 are generated in response to the supply of frames addressed to all stations, subject to the condition of the busy fly knob flow knob 123 and the buffer availability of the frame receiving circuit 102. A received buzzer number frame is provided. At the same time, Busy Flip Flo Nobu 12
3 is reset in response to the generation of a signal on the reset signal line 301, and the reception inhibit flip-flop 124 is set. At this time, since the flip-flop 125 is not set, no busy frame is sent. Therefore, the data transmission device 4 transfers the same frame addressed to all target stations a predetermined number of times until no busy frames are received. However, Busy Flip 70 Tsubu 12
If a frame addressed to all stations that does not send to flip-flops 122 and 130 is given when the receive-prohibiting flip-flop is in the off state with
Frame detection circuit output signal lines 202, 203 and 2
Even if a signal occurs on 04, it can be received signal lines 303 and 3.
Since no signal is generated at 04, the frame receiving circuit 102
is not hot to start. Therefore, even if the data transmission device 4 transmits a frame addressed to the same all stations, double reception will not occur unless the flip-flop 124 of the data transmission device on the receiving side is reset-g. - When the busy frame is no longer returned after sending a frame addressed to all the target stations, the data transmission device 4 transmits a command frame (hereinafter referred to as main) to set the reception inhibit flip-flop 124'r'J in each data transmission device. The example is referred to as the command B frame) is the fourth frame.
The message is sent to all stations in the format shown in the figure, and the series of operations ends. The data transmission device that has received the command B frame generates a signal on the timing signal line 201 when the frame is given to the frame detection circuit 101 in FIG. 3 and the control information portion C in FIG. 4 enters the shift register 111. Tecoder 1
A signal is generated from 12 through signal line 502. In response to the generation of this signal, the transmission prohibition flip-flop 1
24 is reset, and the data transmission device 4 completes the transfer of frames addressed to all stations. However, in response to the supply of a busy frame addressed to the own station, the p-flip knob 130 is set by a signal applied from the tecoder 112 in FIG. 3 via the signal line 503 and a timing signal from the timing signal line 201. Therefore, the receivable signal line 30
Signals are generated at 3 and 304, and the frame reception (i circuit 102 is activated and a busy frame is received.

FIG. 5 shows the transmission operation of frames addressed to all stations as seen from the transmitting side. Each data transmission device at the receiving station prevents data loss and double reception, and data transmission devices that perform transfers other than broadcast communication can transfer data without being aware of broadcast communication. Furthermore, if the buffer is busy due to transfer of broadcast communication, if the buffer becomes empty, it can be kept empty until a frame of broadcast communication arrives (giving priority to broadcast communication).

In the above example, broadcast communication addressed to all stations was explained, but if the signal line 203 in Fig. 3 is replaced with a signal generated during group broadcast communication, the operation will be the same as broadcast communication addressed to all stations,
The present invention can also be applied to group broadcast communications.

Effects of the Invention In the present invention, when a frame of broadcast communication is transferred,
By adopting a configuration in which a status display is provided to request retransmission to the sender without receiving the frame of broadcast communication when it is received in each data transmission device) data loss and double reception of data It is effective in preventing

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a loop transmission system to which the present invention is applied, FIG. 2 is a diagram showing an embodiment of the present invention, FIG. 3 is a diagram showing the entire configuration of the transmission control circuit in FIG. FIG. 4 is a diagram showing a general frame format applicable to the present invention, and FIG. 5 is a flowchart showing a general broadcast communication transfer method on the transmitting side applicable to the present invention. Figures 1 to 3
In the figure, 1 to 4... data transmission device, 11
~14...Transmission line, 30...Optoelectric conversion circuit, 32...Transmission line control circuit, 33...
...Processor, 51,52゜54.55.81~84
, 301-308, 201-205, 207°208.
502,503.71...Signal line, 101...
... Frame detection circuit, 102 ... Frame reception circuit, 103 ... Frame transmission circuit, 1
11...Shift register, 112...
Tecoda, 122-125, 129, 130...
・Flip-flop, 401... NAND circuit,
402...AND circuit, 403...Driver, 404......th/Figure 4 Figure kth

Claims (1)

[Claims] Storage means for storing frames of received broadcast communication in a data transmission device in a data transmission system that transfers frames of a bit sequence through a loop-shaped transmission path between a plurality of data transmission devices. and means that satisfies the conditions of the contents stored in the storage means and does not receive the frame of the broadcast communication when the frame is supplied before the transfer completion report of the broadcast communication is received; 1. A data transmission device comprising means for notifying a transmission source of a retransmission request when a communication frame cannot be received normally.