JPH035702B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an interrupt method for information transmission between a center and a plurality of slave stations.

When transmitting information between a master and multiple slave stations, a polling method is known in which the master queries the slave stations in a predetermined order, and the slave stations that receive the inquiry transmit information to the master. .

On the other hand, Fig. 1 is a block diagram of a card-type vending system, where 1 is a center, 2a, 2b...2n are terminals for reading cards, and each terminal and the center are connected by two signal lines 3. Information is transmitted between the center 1 and each of the terminals 2a, 2b, . . . 2n using a polling method. Each terminal has a numeric keypad 4 for inputting a password and a card insertion slot 5, and the card number and password are read from a magnetic card (not shown) inserted into the card insertion slot 5. 6a, 6b,...6n are each terminal 2a, 2
b...It is a product vending machine installed in 2n.

Each terminal 2a, 2b,... responds to an inquiry from the center 1 and indicates the distinction between the data, such as the card number and PIN number in the case of password verification, and the card number and sales amount in the case of sales data. Send the command to the center.

In the above-mentioned card sales system, when the center 1 and the terminals 2a, 2b, 2c, etc. are connected in a two-wire system and data is transmitted using the polling method, an inquiry is made to all the terminals at a time T. If this is done, each terminal can communicate with the center only once every T time, which results in a long waiting time for customers using magnetic cards.

This invention has been made to eliminate the above-mentioned drawbacks, and provides an interrupt method that allows interrupt communication to be performed using a simple mechanism in a device that performs data communication between a center and a terminal using a polling method. The purpose is to

In order to achieve this objective, the present invention allocates an appropriate bit position in the response period from the terminal to the center as an interrupt request signal bit, and when the center identifies that there is an interrupt request signal at this position. , a signal of n bits corresponding to the total number of terminals is sent from the center to the terminal, and the terminal which issued the interrupt request is made to respond to the bit signal assigned to it. The center identifies which terminal has issued the interrupt request from the position where the pulse is missing.The center makes an inquiry to that terminal using a polling method, and executes the interrupt for that terminal.

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

The following explanation describes an embodiment in which the present invention is applied to the card-type sales system shown in FIG.
In this embodiment, the signal format alternately includes two states, H level and L level, for each bit of transmitted data, as shown in FIG. 4, and when the L level is 0.8 msec. indicates data 0, and when the L level is 1.6 msec, data “1” is indicated.

As shown in Figure 5, the terminal has a transistor Tr connected to the signal line 3, and when transmitting data from the terminal, this transistor
Data "0" is sent to the signal line 3 by turning the Tr on for, for example, 0.8 msec, and data "1" is sent to the signal line 3 by turning the Tr on, for example, for 1.6 msec.

FIG. 2 shows a normal polling type communication form, and... is, for example, the terminals 2a, 2b, . . . 2n in the card-based sales system shown in FIG.
It shows the communication period for. In each period, each terminal 2 receives an inquiry from the center 1 during the inquiry period Tq.
Sends multiple bit data specifying a, 2b, . . . 2n. After an appropriate processing time, predetermined data is returned from the designated terminal to the center 1 during a response period T _A from the terminal. This communication is performed between each terminal and the center in an appropriate numerical order, and this process is repeated. If communication is performed correctly, an OK signal is sent from the center.

In the present invention, an appropriate bit position in the response period _TA , for example, the second bit position bq of the command signal, is assigned to the interrupt request.

Next, interrupt request processing will be explained with reference to FIG.

Now, for example, if a magnetic card is inserted into the terminal 2n during the processing period for the first terminal 2a, an interrupt request is received from the terminal 2n at bit bq of the command signal in the response period T _A of the processing period. 1” is sent. When the center 1 detects the occurrence of this interrupt request, it sends n pulse trains Po to the signal line 3.

Upon receiving this pulse train Po, the n-th terminal device 2n that issued the interrupt request turns on the transistor Tr connected to the signal line 3 at the timing allotted to itself. It responds by dropping the n-th pulse Pon assigned to the machine 2n.

Center 1 is monitoring pulse example Po, and by detecting that pulse Pon is missing,
It recognizes that the n-th terminal 2n has issued an interrupt request, and transmits data specifying the terminal 2a during the next inquiry period Tq. As a result, predetermined data is sent from the terminal 2n to the center 1, and the interrupt processing ends.

If there is no other interrupt request, then the inquiry and communication processing for the second terminal 2b is executed.

During the above interrupt processing, if there is an interrupt request from another terminal, the above n
By setting the interrupt request bit bq of the response period _TA in the interrupt processing of the th terminal to "1",
The next interrupt becomes possible.

Figure 6 shows the data transmitting/receiving section in the terminal, and the in terminal of the input detection circuit 11, which responds only when an inquiry from the center is made, is connected to the signal line 3, and from the falling edge of the signal at this in terminal, After an appropriate time, the state of the signal line 3 is sampled, and whether the state is high level or low level is temporarily stored.
Then, at the rising edge of the signal at the in terminal, a signal is output to the clock terminal CK to send the stored result to the shift register 12 from the DATA terminal, and the contents of the shift register 12 are shifted leftward in the figure. The above operation is repeated for the inquiry period command from the center 1. and,
The data representing the number of terminals to which the inquiry from the center is directed is stored in the shift register 12 and sent to the command analyzer 13.

On the other hand, the terminal number setting switch 14 sends a code signal representing the number of its own terminal to the command analyzer 13.
The set value is compared with the number specifying the terminal from the center stored in the shift register 12, and if they match, the contents of the command from the center 1 are read. If the content of the command is sales data, the sales data stored in the sales data storage circuit 15 is written into the output register 16. The data written in the output register 16 is read out by the output circuit 17 when a command is received from the center, and is sent to the signal line 3 by turning on and off the transistor 18. Note that the output circuit 17 is controlled so as not to operate while a command signal is being sent from the center 1.

The interrupt processing in FIG. 6 is performed as follows.

For example, when a magnetic card is inserted into the terminal 2n and a password is entered, the contents are written into the password memory 20. The input terminal of the analyzer 13 indicates that this password has been written.
If entered in 2, the inquiry period from center 1
After the completion of Tq, the second bit of the output register 16 is set to 1,
0 is written to the other bits.

Thereafter, the contents of this output register 16 are read out to the output circuit 17 by the synchronization pulse from the center 1, and at the second bit position bq of the period T _A , the transistor 18 is turned on and an interrupt request is issued. Signal line 3
Output to. After outputting this interrupt request, the analyzer 13 reads the terminal number n applied from the terminal number setting switch 14, and writes 1 to the nth bit of the output register 16 in correspondence with the number n. Other bits are 0.

On the other hand, when the interrupt request is read by the center 1, n pulses Po are sent to the signal line 3. In accordance with this pulse, the contents of the output register 16 are read out by the output circuit 17 starting from the first bit. When the nth bit of data "1" is read out, the transistor 18 is turned on and the pulse train is turned on.
The nth pulse Pon of Po is missing.

When the center 1 reads the missing pulse Pon, it informs the center that it is the nth terminal 2 that issued the interrupt request.
It identifies that it is n and executes an interrupt for this terminal.

As mentioned above, by performing interrupt processing in the card-based sales system, the waiting time when the customer inserts the card into the terminal is eliminated.
This eliminates the problem of customers having to wait unnecessarily.

As detailed above, the present invention provides a space for issuing an interrupt request signal at a specific position during the signal transmission period from the terminal to the center in a device that normally communicates between a center and a terminal using a polling method.
Since the center determines interrupt requests based on the information in this space, interrupt requests can be easily identified and can be easily applied to systems that transmit signals using a two-wire method. Can handle interrupts. In addition, an interrupt request can be executed simply by turning on a switch installed in the transmission line and extinguishing the pulse assigned to the own station, so the circuit configuration is simple, especially for relatively simple applications such as vending systems. Suitable for data transmission between devices.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a card-based sales system, FIG. 2 is a diagram showing an outline of a polling system, FIG. 3 is a diagram showing an embodiment of an interrupt system of the present invention, and FIG. Figure 3 is a waveform diagram showing an example of the signal format used in the embodiment, Figure 5 is a diagram showing an example of the output part of the terminal used in the sales system of Figure 1, and Figure 6 is an example of the terminal. FIG. Tq...Inquiry period from the center, T _A ...Response period from the terminal to the center, bq...Interrupt request signal bit, 1...Center, 2a, 2b,...2n...
...Terminal, 3...Signal line.

Claims (1)

[Claims] 1. Communication between the center and terminals is normally carried out using a polling method, and a specific period during which the terminals respond to inquiries from the center is allocated as an interrupt request period.
A pulse is sent from the center to each terminal, and the terminal that requires an interrupt turns on the switch installed in the data transmission path of each terminal at the timing assigned to that terminal during this interrupt request period, and transmits the above pulse. among them, erase the pulse assigned to the relevant terminal,
When the center detects an interrupt request due to the disappearance of this pulse, it sends a signal with a predetermined number of bits to each terminal, and causes the terminal that issued the interrupt request to respond with the bit position assigned to it. , an interrupt method characterized in that the center identifies the terminal that has made the interrupt request and executes the interrupt.