JPH012441A - Communication control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a communication system 6I1g device that performs serial data communication between one master station and a plurality of terminal stations.

(Prior art) Conventionally, this type of master station communication control device has been designed to perform serial data communication to one terminal, but not to multiple terminals. . However, serial data communication can be performed with a plurality of terminals using this type of communication control device by a method as shown in FIG.

That is, while the control signal line ER is off (low level), the terminal number selection pulse A is output to the data sending line SD, and while the signal line ER is on (high level), the serial signal B is output to the data sending line SD. Send to. A specific partner terminal can be selected from among a plurality of terminals by the terminal number selection pulse A, and serial data communication can be performed between the master station and this terminal. However, the serial signal B is υ(can be easily outputted using a parallel-to-serial converter LSI installed in the communication control device of the station), and the terminal number selection pulse △ is the communication system 1j.
It must be created by a program using a microprocessor or the like installed in the lli. However, this program changes the data transmission line ER to a high level and a low level at fixed time intervals equal to the number of pulses of the terminal number selection pulse A after confirming that no data is being sent or received between the master station and the terminal. And it becomes quite complicated. For this reason, there was a drawback that the load was placed on the IPU, slowing down the execution of other programs, and deteriorating the communication control device.

(Problem to be solved by R) Conventionally, in order to perform serial data communication between one master station and multiple terminals, the master station had to create a terminal number selection pulse to identify the terminal by a program. This puts a burden on the MP'U of the communication control device of the master station, which has to transmit the data, which delays the processing of other programs and deteriorates communication efficiency. Therefore, the present invention aims to eliminate the above-mentioned drawbacks, and aims to provide a communication control device that can reduce the load on the MPU and improve communication efficiency by generating terminal number selection pulses using hardware. The purpose is

[Configuration of the Invention (Means for Solving Problems)] The present invention generates a terminal address selection pulse corresponding to the address of the terminal to select a communication partner terminal from among a plurality of terminals, and then In a communication control device that transmits and receives serial data between a second counter that stops the operation of the first counter when the count value of the first counter reaches the set value; and a second counter that generates a predetermined signal when a pulse constituting the serial data on the transmission/reception signal line is input. a multivibrator that outputs the value to the microprocessor of the communication control device; and after the microprocessor confirms that there is no serial data on the transmission/reception signal line based on the output value of the multivibrator, the second counter is set to the numerical value. and a control means.

(Function) In the communication control device of the present invention, the control means transmits/receives fg
After confirming to the MPU of the communication control device that there is no serial data on the transmitting/receiving signal line from the output value of the multivibrator that inputs the pulse on the signal line, a value corresponding to the terminal address to be communicated is input to the second counter. Let it be set. As a result, the second counter activates the first counter, so that the first counter 1 outputs a runt output terminal address selection pulse onto the transmission/reception signal line. Second
The counter stops the operation of the first counter when the count of the first counter reaches the set value.

(Embodiment 1t) An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram showing one embodiment of the communication control device of the present invention. 1 is a microprocessor (MPU) that controls the entire device; 2 is a parallel-to-serial conversion LSI that mutually converts parallel data to serial data; 3 is a driver that transmits data to the data transmission line SD; 4 is the data reception line RD a receiver receiving data from 5
1-lime sends a control signal to the control signal line ER, 6 is a gate that picks up signals on the data transmission/reception lines SD and RD, 7 is a retriggerable monostable multivibrator that generates an interrupt signal to MPLll, 8 9 is a rising delay circuit that delays the output of the retriggerable monostable multivibrator 7; 9 is a presettable down counter in which a value corresponding to the terminal address is set and controls the counting operation of the counter 10; 10 is a presettable down counter that corresponds to the terminal address. A clear counter 11 outputs a terminal address selection pulse 100, and 11 is a gate that outputs a low level when one of its inputs becomes a low level, and outputs either serial data or a terminal address selection pulse. 12 is an inverter that inverts the output of the clear force counter 10, and 13 is an oscillator that generates a signal to drive the clear counter 10.

Next, the operation of this embodiment will be explained. First, when starting communication, N, IPU 1 is the data transmission and reception line S.
The rise delay circuit 8 detects that there is no signal on D and RD.
Due to the signal from jff 32. Then, a high-level signal is outputted to the parallel-serial conversion LSI 2 to the driver 5, and the control signal line ER is set to a low level to enter the terminal address selection mode. Next, \+PU1 sets a numerical value corresponding to the address of the communication destination terminal in the presettable down counter 9. Presettable counter 9
When the numerical value is set, the signal line 51 is set to low level and the clear counter 10 is activated. As a result, the clear size counter 10 outputs a count pulse to the signal line 52 via the inverter 12 as a terminal address selection pulse 200. This terminal address selection pulse 200 is input to the driver 3 via the gate 11 and sent to the data transmission line SD, and is also input to the presettable down counter 9. The presettable down counter starts counting down from the set value in synchronization with the input of the terminal address selection pulse 200. Stop operation.

Therefore, the terminal address selection pulse 2 has the same number of pulses as the value set in the presettable down counter 9.
00 is sent out on the data transmission line SD. On the other hand, if the signal line 51 becomes high level when the count of the presettable down counter 9 reaches 1 or O, this is input to the B input terminal of the retrievable monostable multi-vibrator 7, and the retrievable monostable The Q output terminal of the table multi-by-break is set to low level. After this low level signal is delayed for one hour by the rise delay circuit 8, it is output as an interrupt signal to ~4PU1 via the signal line 53, notifying ~IPU1 that the selection of the terminal address has been completed. As a result, M P
Lll outputs a low level signal to the driver 5 via the parallel-to-serial conversion LSI 2, and sets the control line ER to a high level to enter the data sending mode. That i! 2
i'v IPU 1 gives parallel data to parallel-serial converter LSI 2 in order to send data, and LSI 2 converts this parallel data into serial data and sends it to driver 3 from output terminal TXD via gate 11.
and sends it out on the data transmission line SD.

On the other hand, during reception, the receiver 4 receives the serial data on the data reception line RD, converts it into parallel data by the parallel-serial conversion LS'I2, and supplies it to ~IPU1. Also, when this communication control device is transmitting and receiving signals during transmission and reception, a transmission or reception pulse is input to the exclusive OR gate 6, and the data is sent to the input terminal of the retriggerable monostable multivibrator 7 via this OR gate 6. A pulse is input.

Therefore, during this time, the output terminal of the multi-high break 7 maintains a low level, and this low level signal is input to ~IPU1 via the rising delay circuit 8, so that the M
PU1 can recognize that its own device is currently transmitting and receiving data.

Conversely, when a high level signal is input from the signal line 53, M
PU1 confirms that there is no signal on the data transmission/reception lines SD, RD.

According to this embodiment, since the terminal address selection pulse 200 is generated by hardware using the presettable down counter 9 and the counter 10 with clear, the MPU
To efficiently perform serial data communication with multiple terminals without placing a burden on one terminal.

[Effect of the invention 1 As described above, according to the communication control device of the present invention, by creating the terminal number @ selection pulse by hardware,
This has the effect of reducing the burden on the MPU and improving communication efficiency.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the communication control device of the present invention, and FIG. 2 is a time chart illustrating an example of the operation of a conventional communication system TAII device. 1...Microprocessor (MPU > Parallel-serial conversion LSI) 3.5...Driver 4...Receiver 6...Exclusive OR game i~ 7...S1~Recouple monostable Multi pie break 9...Presettable down counter 10...Counter with clear 11...Go to game agent Patent attorney Nori Chika Ken Yumukai Sanno - 10 clear 1st i Kunta 1st figure

Claims (1)

[Claims] After generating a terminal address selection pulse corresponding to the terminal address and selecting a communication partner terminal from among multiple terminals, the communication control device that transmits and receives serial data to and from this terminal selects the terminal address selection pulse corresponding to the terminal address. a first counter that generates a corresponding terminal address selection pulse; and when a numerical value is set, the first counter is started; and when the count value of the first counter reaches the set value, the first counter is activated; A second counter that stops its operation, a multivibrator that generates a predetermined signal when the pulse forming the serial data on the transmitting/receiving signal line is input, and a multivibrator that generates the serial data on the transmitting/receiving signal line based on the output value of this multivibrator. and control means for causing the second counter to set the numerical value after the MPU confirms that the numerical value is not present.