JPH04205365A - Data communication equipment - Google Patents

Abstract

PURPOSE:To freely change the communication speed of a communication line by transferring communication speed information from a central processing circuit to a line control circuit in transmission, and transferring reception speed information in reception data to the central processing circuit in reception. CONSTITUTION:In the transmission, information representing desired transmission speed is written on a register 6a from a CPU 5 via a bus 9. The information is sent to a communication line control unit 8, and data stored in memory 7 is transmitted to a line 10 at transmission speed based on the information. In the reception, reception speed data on the line 10 is fetched by the communication line control unit 8, and the data is written on a communication speed register 6b, and is sent to the CPU 5. Also, the communication line control unit 8 receives the data based on the data representing the reception speed, and it is stored in the memory 7 under the control of the CPU 5. In such a way, operability can be improved, and the degree of freedom for speed selection can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Application Field) The present invention relates to a data communication device, and particularly to a data communication device capable of transmitting and receiving data at a plurality of communication speeds.

(Prior art) Recently, L A N (1 local area net
It is widely used to connect computers and terminals such as computers and terminals via communication lines to mutually transmit data.

This communication line is interfaced with a protocol such as R9-232C, and an appropriate communication speed is selected from among a plurality of communication speeds depending on the situation.

FIG. 2 is a diagram showing the configuration of an example of a communication circuit of a conventional data communication device.

As shown in the figure, the communication circuit of the conventional data communication device is composed of a line control device 1, a clock selector 2, and a communication speed changeover switch 3.

Clock selector 2 has taro clock CKI and clock CK.
2 has been input. Then, when the operator switches the communication speed selector switch 3, either the clock CKI or the clock CK2 is outputted to the output of the clock selector 2. This clock is input to the line control device 1. In the case of reception, data is received from the four-wire 4 based on this clock, and in the case of transmission, data is output to the line 4.

However, the above-mentioned conventional data communication device is equipped with hardware such as the communication speed changeover switch 3, which increases the size and cost, and requires the hassle of operating the communication speed changeover switch 3 every time the communication speed of the line is changed. There was a sense of dignity.

(Problems to be Solved by the Invention) As mentioned above, conventional data communication devices are equipped with hardware such as a communication speed selector switch, which increases the size and cost, and requires communication There was the hassle of operating the speed selector switch.

The present invention was devised to solve the above-mentioned drawbacks, and an object of the present invention is to provide a data communication device that requires less hardware, lowers costs, and improves operability.

[Configuration of the Invention (Means for Solving the Problems)] The data communication device of the present invention includes a central processing circuit that controls data communication processing, and, at the time of transmission, based on transmission speed information from the central processing circuit. A data communication device comprising: a line control circuit that outputs the received data to a communication line, and transfers receiving speed information in received data inputted from the communication line to the central processing circuit at the time of reception.

(Function) In the data communication device of the present invention, at the time of transmission, communication speed information is first transferred from the central processing circuit to the line control circuit.

Then, the communication control circuit outputs the transmission data to the communication line at a speed based on this transmission speed information.

Further, during reception, the reception speed information in the reception data is transferred to the central processing circuit.

Therefore, the communication speed of the communication line can be freely changed by the central processing circuit.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a data communication device that is an embodiment of the present invention.

As shown in the figure, the data communication device of this embodiment includes a CPU 5 that controls transmission and reception data processing, etc., communication speed registers 2a and 2b that write communication speeds, a memory 7 that stores communication data, and a line control system. It consists of a device '8.

The CPU 5, communication speed registers 6a and 6b, memory 7, and line control device 8 are connected by a bus 9.

Further, the communication speed registers 6a and 6b are connected to the line control device 8, so that they can exchange communication speed information with the line control device 8.

Next, the operation of the data communication device configured as described above will be explained.

First, a case in which data is transmitted from a data communication device will be described.

Information indicating the desired transmission speed is written from the CPU 5 to the register 6a via the bus 9. This information is transmitted to line controller 4.
The data stored in the memory 7 is transmitted to the line 10 at a transmission speed based on this information.

Next, the operation when the data communication device receives data will be explained.

First, the line control device 8 extracts the reception speed data on the line 10 and writes this data into the communication speed register 6b. Furthermore, this data is sent to the CPU 5. Further, the line control device 8 receives the data based on the data indicating the reception speed. The data is then stored in the memory 7 under the control of the CPU 5.

Therefore, according to the data communication device of this embodiment, hardware such as a communication speed switching device is not required, and the CPU can control the software using software, improving operability and increasing the degree of freedom in speed selection. .

[Effects of the Invention] As explained above, according to the data communication device of the present invention, hardware such as a communication speed changeover switch is not required, so that cost and size can be reduced. In addition, the communication speed can be selected under the control of the central processing circuit, improving operability and increasing the degree of freedom in speed selection.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a data communication device according to an embodiment of the present invention, and FIG. 2 is a diagram showing the configuration of a conventional data communication device. 5... CPIJ, 6a, 61)... Communication speed register, 7... Memory, 8... Line control circuit, 9... Bus, 1.0... Communication line. Applicant Toshiba Corporation Representative Patent Attorney Sasa Suyama −

Claims (1)

[Claims] (1) A central processing circuit that controls data communication processing, and when transmitting, outputs transmission data to a communication line based on transmission speed information transferred from the central processing circuit, and when receiving, receives data input from the communication line. A data communication device comprising: a line control circuit that transfers reception speed information in data to the central processing circuit.