JPH0616623B2 - Information transmission method - Google Patents

Description

Description: (1) Technical Field of the Invention The present invention relates to an information transmission method capable of efficiently responding to an outgoing call request from a terminal with hardware having a small number of central processing units or terminal control devices.

(2) Background of Technology In a system in which a central processing unit CPU controls a large number of terminals TM scattered on the order of a thousand through a plurality of terminal control units TMC as shown in FIG. It is common practice to control a number of terminals TM on the order of a hundred. It has been put into practical use to have a meeting by a polling method or a contention method when starting information transmission between them.

(3) Prior Art and Problems The polling method is executed by, for example, the configuration of the terminal controller and the terminal of the totalizer system shown in FIG. Further, FIG. 3 shows an operation time chart of FIG.
In FIG. 2, both the terminal control device and the terminal are equipped with a microprocessor μCPU for operation control. ME is a storage device, HCC is a central processing unit coupling unit, TCM is a terminal control unit, and polling from the μCPU via the bus control unit BSC is performed from the transmission / reception reset device T / R to the driver DV, and from the μCPU. Terminal address A signal is decoder DEC
After 1, the driver DV is reached and polling is sent to the target terminal. The terminal at that address reports the presence or absence of data to be sent to the central processing unit. In the time chart shown in FIG. 3, the data A that terminal # 3 should initially send
Even when D is generated, polling is sequentially performed from the terminal # 0. Therefore, the terminal # 3 is polled after at least 30 mS and sends out the data AD. The terminal control device TMC sends back the response data RD. Terminal TM
Sends a confirmation signal A. The terminal control unit TMC transmits again sequentially from polling P0. When the data generation of the terminal # 1 is just before the polling starts, the polling can be performed and the data can be transmitted with almost no waiting. At this time, it takes about 10 minutes to start polling, send data, and return a response.
mS is required. Compared with the time (turnaround time) of about 50 mS from generation of data AD to confirmation signal A after response, the above 10 mS is short, but when there are a large number of terminals without transmission data AD, they are all Polling with a delay delays polling of the terminal where the transmission data occurs. However, since the terminal control device only needs to receive information from one terminal, the transmission control unit TRC and other hardware can be small in amount, and the software of the processor is simple.

Although the hardware of the terminal control device increases, the contention method has been put into practical use in order to shorten the turnaround time. FIG. 4 shows a configuration diagram and FIG. 5 shows a time chart. In FIG. 4, the same symbols as those in FIG. 2 indicate the same components, and the transmission control unit TCT and the transmission / reception switch T
/ R is provided corresponding to each terminal, and is a bus control unit BSC.
Is larger than that shown in FIG. Further, the transmission control unit TCT of each terminal is equipped with a signal generator which activates the corresponding transmission control unit of the terminal control device TMC when the data AD to be transmitted is generated. As shown in FIG. 5, when the terminal # 3 notifies the terminal control device TMC of the occurrence of the transmission data AD, the terminal control device TMC may start receiving the data immediately. Return the response data RD. The terminal # 3 sends the confirmation signal A. The time required from the generation of the transmission data AD to the end of the transmission of the confirmation signal A is about 45 mS. Although FIG. 5 shows that the transmission data AD is generated in the terminal # 1 after a while after that, even if this data is generated during the transmission from the terminal # 3, the terminal control device TMC is I can deal with it. Therefore, when viewed from the terminal, it is not necessary to wait from the generation of transmission data until the start of transmission, so the turnaround time is short and the point of data transmission is preferable, but the hardware in the terminal control device becomes huge and the software is complicated. Becomes

(4) Object of the invention The object of the present invention is to improve the above-mentioned drawbacks and to provide an information transmission system in which the terminal control device is configured with a small amount of hardware and each terminal can perform data transmission with a short waiting time. To provide.

(5) Structure of the Invention According to the structure of the present invention for achieving the above-mentioned object, a system in which a central processing unit controls a large number of terminals via a plurality of terminal control units provides a serial transmission line between the terminal control units and the terminals. In the method of transmitting information by means of the above, the serial transmission line is composed of a downlink data line for transmitting information from the terminal control device to the terminal and an uplink data line for transmitting information from the terminal to the terminal control device, and to the terminal control device, A trigger register having a memory bit corresponding to each terminal which is turned on when each terminal receives a polling request signal notified by turning on the rising data line and turned off when the μCPU writes "0". To provide. The μCPU of the terminal control device constantly monitors the trigger register, specifies the address of the terminal that has issued the polling request signal based on the ON bit of the trigger register, and specifies the specified terminal. , The terminal sends a polling signal through the down data line, and when the terminal receives the polling signal through the down data line, the terminal performs normal request data transfer using the up data line.

(6) Embodiment of the invention Fig. 6 is a diagram showing the structure of an embodiment of the present invention, Fig. 7 is an operation time chart of Fig. 6, and the same reference numerals as those in Figs. ing. In FIG. 6, the terminal control device TMC is provided with as many trigger registers TRG as the number of terminals to which the output of the receiver RV from each terminal TM is applied correspondingly.

The trigger register TRG is a set of normal flip-flop circuits, and 1 bit corresponds to one terminal TM. The trigger signal is a signal for the terminal TM having a request for information transmission to notify the terminal control device TMC that there is a request for transmission, and specifically, it is sent to the information transmission line (data line) during non-communication. It is an ON signal having a width equal to or longer than the clock signal cycle of the triggered trigger register. The trigger register is automatically set at the rising edge of the ON signal issued from the terminal TM (first clock after signal arrival). It is also set by the μCPU of the terminal control unit TMC reading this data via the bus control unit BSC and then by writing “0” via the bus control unit BSC.

In FIG. 6, when transmission information is generated in the terminal, the μCPU of the terminal specifies transmission of a trigger signal to the transmission control unit TCT via the bus control unit. An OR gate is provided to directly send the ON signal from the transmission control unit TCT. This gate is also used to send out the signal from the T / R when performing a normal request data transfer. The transmission control unit TCT sends out a trigger signal in which a signal is input to the driver DV input. When a trigger signal enters the receiver RV of the terminal control unit TMC, "1" is set in the corresponding bit of the trigger register TRG. ΜCPU of terminal control unit
Since it constantly monitors this gate TRG via the bus control unit, it can know the number of the terminal with information, specify the address of that terminal, and use T / R to poll the terminal. And then receives data from the terminal. Terminal # as shown in the time chart of FIG.
The transmission data generation signal AD of No. 3 is the trigger register TRG #
3 is set (ADF), and when the terminal controller TMC knows the set, polling P3 is issued. The terminal receives it and sends out the data AD. Terminal control device TMC
Takes 5 seconds to monitor all trigger registers RG.
mS, from polling P3 to confirmation signal A
It is 50 mS. Here, the turnaround time will be compared with other methods. FIG. 7 shows the search time and execution time of the trigger register. In FIG. 3, it is the sum of the time required for the polling to reach its turn from the generation of AD and the execution time. In FIG. 5, only the execution time is shown. In FIG. 7, the search time of the trigger register TRG and the polling arrival time increase in proportion to the number of terminals, but since the search time is about 5 mS in register processing, it can be ignored for the execution time, but the average polling arrival time Since the transmission time is at least 2 bytes x number of units / 2, it is greatly affected by the number of units. In a system with an extremely large number of terminals, the turnaround time relationship is as shown in Fig. 3> Fig. 7> Fig. 5.

When transmission information to the terminal is generated in the terminal control device TMC, the address of the other terminal is set to the address A in the transmission control unit.
And the decoder 1 and the decoder 2 are transmitted to the address B.
Is decoded and the line gate with the corresponding terminal is turned on. In this state, the μCPU sends T via the bus control unit BSC.
When information is written in / R, it is transmitted to the terminal through the gate and driver DV, and when it is finished, the T / R notifies the buffer is empty, so the next data is written in T / R. When all the information is repeatedly ended, when the reading is designated in the transmission control unit, the T / R is set to the read mode. When the μCPU of the terminal TM receives all the information through the bus control unit BSC, it commands the transmission control unit to write, and
When R becomes write mode, write response information to T / R,
It is sent to the terminal control device TMC. The terminal control device TMC reads the response information via the T / R and the transmission is completed. When transmitting to another terminal, the address control is changed and the same control is performed, and when all are completed, the register TRG is monitored again.

Although FIG. 6 illustrates an example of three terminals, when the number of terminals is large, a driver, a receiver, a gate, a trigger register T
It goes without saying that by increasing RG, it can be dealt with.

(7) Effects of the Invention According to the present invention as described above, in a terminal control device that transmits information to a plurality of terminals, the terminal control device has a small hardware configuration such as a trigger register, one transmission control circuit, and a terminal selection circuit. , Each terminal can send data with less waiting time. In addition, the provision of a trigger register as hardware means that
This has the effect of simplifying the address designation of the requesting terminal to be designated by the CPU, making unnecessary the complicated program to be prepared by the μCPU of the terminal control device, and reducing the load.

[Brief description of drawings]

FIG. 1 is a diagram explaining that a terminal control device controls a large number of terminals, FIG. 2 is a diagram showing a configuration of a conventional polling method, FIG. 3 is an operation time chart of FIG. 2, and FIG. FIG. 5 is a diagram showing a configuration of a conventional contention system, FIG. 5 is an operation time chart of FIG. 4, FIG. 6 is a diagram showing a configuration of an embodiment of the present invention, and FIG. 7 is an operation time chart of FIG. Is. CPU: Central processing unit TMC: Terminal processing unit TM: Terminal μCPU: Microprocessor ME: Storage device TCT: Terminal control unit DV: Driver, RV: Receiver TRG: Trigger register

Claims (1)

[Claims] 1. A system in which a central processing unit controls a large number of terminals via a plurality of terminal control units to transmit information between the terminal control units and the terminals via a serial transmission line, wherein the serial transmission line is a terminal control unit. From the terminal to the terminal, and the uplink data line to transmit information from the terminal to the terminal control device, the terminal control device, each terminal to notify by turning on the upstream data line polling request A trigger register having a memory bit corresponding to each terminal which is turned on when a signal is received and turned off when the μCPU writes “0” is provided, and the μCPU of the terminal control device sets the trigger register. Always monitor and specify the address of the terminal that issued the polling request signal based on the bit that is turned on in the trigger register. Then, the polling signal is transmitted to the designated terminal through the downlink data line, and when the terminal receives the polling signal through the downlink data line, normal request data transfer is performed using the uplink data line. Characteristic information transmission method.