JPH0533861B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a communication control device that performs data communication using a multi-drop method, either by wire or wirelessly.

Prior Art As shown in FIG. 3, a conventional multi-drop type communication control device receives serial data from a communication line 11, converts each byte into parallel data by a serial/parallel conversion circuit 14 via a receiving circuit 13 converted and each time the conversion is completed,
An interrupt signal is generated, and this interrupt signal requests the control circuit 15 to read data. When the control circuit 15 receives the interrupt signal, the control circuit 15 receives the interrupt signal from the serial/parallel conversion circuit 14, one byte at a time.
The received data is read, and if the data is addressed to itself, it is subjected to processing necessary for data communication such as error handling within the control circuit 15, and then outputted to a terminal (not shown) via the transmission circuit 12.

On the other hand, if the data is not addressed to itself, the received 1
It discards all data for the packet and waits until receiving the next packet addressed to itself.

Problems to be Solved by the Invention However, in the conventional communication control device described above, all data addressed to itself and other data are taken into the control circuit, and the control circuit judges whether the data is addressed to itself or not. However, since the system is such that only the data addressed to itself is taken in and all other data is discarded, processing time is also required to process the reception of data addressed to other than the self. The problem arises in that the more communication control devices are connected to a communication line in a multi-drop manner, the more time is wasted in receiving data that is not addressed to the device itself.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a communication control device that can shorten the time required for processing to receive data that is not addressed to itself.

Means for Solving the Problems In order to achieve the above object, the present invention provides a transmission circuit for transmitting data onto a communication line, a reception circuit for receiving data from the communication line, and a control circuit. a serial/parallel conversion circuit for converting parallel data to serial data; a retriggerable monomulti circuit driven by an interrupt signal from the serial/parallel conversion circuit;
The device includes a gate circuit that controls the interrupt signal using the output of the retriggerable monomulti circuit, and a control circuit that exchanges parallel data with the serial/parallel conversion circuit.

Effects According to the present invention, with the above-described configuration, when the control circuit section determines that the received data is not addressed to itself, the retriggerable mono multi-circuit is activated while receiving one packet.
By continuing to maintain the set state and inputting its output signal to the gate circuit, the interrupt signal from the serial/parallel conversion circuit is prohibited from being input to the control circuit, thereby receiving data that is not addressed to the self. Avoid using the time that would otherwise be spent when doing so.

Embodiment FIG. 1 is a block diagram showing a communication control device according to an embodiment of the present invention. In FIG. 1, 1 is a multi-drop type communication line, and 2 is a transmitting circuit for transmitting data to the communication line 2, which has a data input terminal 22 and a data output terminal 21. 3 is a receiving circuit that receives serial data from the communication line 2, and includes a data input terminal 31 and a data output terminal 3.
It has 2. 4 is a serial/parallel conversion circuit, which includes a serial data output terminal 41, a serial data input terminal 42, and a parallel data input/output terminal 4.
3. It has an interrupt signal output terminal 44. 5 is a control circuit, which includes a parallel data input/output terminal 51, an interrupt signal input terminal 52, and a retriggerable monomulti circuit 6.
It has a control signal output terminal 53 for controlling the data bus, and a terminal (not shown) side data bus input/output terminal 54. 6
is a retriggerable monomulti-circuit and has an interrupt signal input terminal 61, a gate control signal output terminal 62, and a set/reset control signal input terminal 63.
A gate circuit 7 has an interrupt signal input terminal 72, a gate control signal input terminal 71, and a gate signal output terminal 73.

To further explain the operation of the communication control device having the above-described configuration, when a series of data as shown in FIG. 4 is input. The serial/parallel conversion circuit 4 converts the data into parallel data and outputs it, and at the same time generates an interrupt signal.

The interrupt signal is input to the retriggerable monomulti circuit 6 and the gate circuit 7. The retriggerable monomulti circuit 6 is normally in a reset state by a control signal from the control circuit 5, the gate circuit 7 is in an open state, and the interrupt signal is
The signal is input to the control circuit 5 via the gate circuit 7. When the interrupt signal is input, the control circuit 5
Read parallel data from the serial/parallel conversion circuit 4.

According to the above sequence, data is received one after another, but when address data is received, it is determined whether the data is addressed to the self or not, and if the data is addressed to the self, data reception is continued in that state. continue. On the other hand, if the data is not addressed to itself, the reset of the retriggerable monomulti circuit 6 is released and the trigger is enabled. When an interrupt signal is input in such a state, the retriggerable monomulti circuit 6 is triggered, generates an output signal with a constant pulse width, and outputs an output signal to the gate circuit 7.
Enter. An interrupt signal is input to the other input terminal 72 of the gate circuit 7, but since the gate is in a closed state, no gate output signal is output.

Now, if the time constant of the retriggerable monomulti circuit 6 is set longer than the data interval (time interval between bytes) T received from the communication line 1, the remaining series of data (one packet worth) During reception, retriggerable mono multi-circuit 6
From then on, the control signal is constantly output, so no interrupt signal is input to the control circuit 5.
On the other hand, the control circuit 5 reads the output state of the retriggerable monomulti circuit 6 at an appropriate timing,
After confirming that there is no output signal, the retriggerable monomulti circuit is reset to return to the initial state.

Effects of the Invention As mentioned above, by preventing the hardware from inputting an interrupt signal when receiving data that is not addressed to the user, the time required for data reception processing can be saved, and that time can be used for other jobs. (for example, terminal control).

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a communication control device according to an embodiment of the present invention, Fig. 2 is a timing chart for explaining the operation of the same device, and Fig. 3 is a block diagram of a conventional communication control circuit. . 1... Communication line, 2... Transmission circuit, 3... Receiving circuit, 4... Serial/parallel conversion circuit, 5...
...Control circuit, 6...Retriggerable monomulti circuit, 7...Gate circuit.

Claims (1)

[Claims] 1. A communication control device that performs data communication using a multi-drop method using wired or wireless communication, which includes a transmitting circuit for transmitting data onto a communication line, and a receiving circuit for receiving data from the communication line. , a serial/parallel converter circuit for converting parallel data between control circuits into serial data, a retriggerable monomulti circuit driven by an interrupt signal from the serial/parallel converter circuit, and the interrupt signal a gate circuit that controls the output of the retriggerable monomulti circuit, and a control circuit that exchanges parallel data with the serial/parallel conversion circuit, and the control circuit controls the output of the data received from the communication line. By determining the address data, it is determined whether the data is addressed to the self, and if the data is addressed to the self, the data following the address data is continuously fetched, and if the data is not addressed to the self, the above By keeping the retriggerable monomulti circuit in the set state while receiving one packet and inputting its output signal to the gate circuit, the interrupt signal from the serial/parallel conversion circuit is input to the control circuit. A communication control device characterized by prohibiting communication.