JPH06164671A - Start-stop synchronization type data communication equipment - Google Patents

Abstract

PURPOSE:To provide a start-stop synchronization type data communication equipment to be automatically turned to a communication enable state only by connecting a line without necessity for a user to input a start-stop synchronization type format. CONSTITUTION:Concerning the start-stop synchronization type data communication equipment for two stations, an initializing signal for setting a baud rate is transmitted in an initializing signal transmission processing ST22 for setting the baud rate at the station for which the start-stop synchronization type format is fixed and continuously, an initializing signal for setting a character length, parity bit, and stop bit is transmitted in an initializing signal transmission processing ST23 for setting the character length, parity bit and stop bit. On the other hand, the baud rate on the side of a communicating party is judged in a baud rate setting processing step ST25 at the station on the side where the initializing signal is received, and the kinds of the character length, parity bit and stop bit on the side of the communicating party are judged and set to an IC for communication in a character length, parity bit and stop bit set processing ST26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an asynchronous data communication apparatus for transmitting and receiving data between a transmitting station and a receiving station by an asynchronous method based on a predetermined format.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a conventional start-stop synchronous data communication device. In the figure, reference numeral 1 is an input device such as a switch and a keyboard for selecting a start-stop synchronization format (baud rate, character length, parity bit, stop bit), 2 is a digital input circuit, and 3 is a signal from the digital input circuit 2. A processor for controlling a communication IC 5 described later, 4 is a processor bus, 5
Is a communication IC for performing parallel / serial conversion and modulation / demodulation of communication data, and the transmitter station device 6 is configured as described above. Reference numeral 7 is a receiving station device on the communication partner side, and 8 is a transmission line connecting the both devices 6 and 7. The receiving station device 7 also includes the same devices as 1 to 5.

FIG. 3 shows a communication IC 5 by the processor 3.
3 is a flowchart showing the initial setting to [1]. In the figure, ST11 is a baud rate selection setting process, ST12 is a character length selection setting process, ST13 is a parity bit selection setting process, ST14 is a stop bit selection setting process,
ST15 is a communication start time determination process.

Next, the operation will be described. The conventional start-stop synchronous data communication device is configured as described above, and, for example, the user inputs the start-stop synchronous format from the input device 1. The processor 3 starts setting the communication IC 5 based on the data input from the input device 1. First, the baud rate is set in the communication IC 5 in the baud rate selection setting process ST11, and the character length is set in the communication IC 5 in the character length selection setting process ST12. Similarly, the parity bit and the stop bit are set in the communication IC 5, and in the communication start timing determination process ST15, it is confirmed that the communication partner is in the ready state, that is, the communication enabled state, and the communication is started. Also in the receiving station device 7, the same asynchronous format is input by the user from the input device and the same processing is performed. As described above, in the asynchronous data communication device, smooth data communication can be performed under the condition that the same format is set in the transmitting and receiving station devices in advance.

[0005]

Since the conventional start-stop synchronous data communication device is constructed as described above, efficient processing is possible when communication is always performed in a constant start-stop format. However, when it is necessary to change this format, the user has to input the start-stop synchronization format in both communication devices through the input device each time the user changes it. Therefore, for example, when one of the communication devices is installed in a high place that is difficult for humans to reach, there is a problem that dangerous work or inefficient work is involved in changing the start-stop synchronization format. there were.

The present invention has been made in order to solve the above problems, and even when the user changes the start-stop synchronization format, the user only has to input the changed format from one communication device. An object is to obtain a synchronous data communication device.

[0007]

According to the start-stop synchronization type data communication device of the present invention, the transmitting station confirms a communicable state, and before starting data transmission, 1,0, Is repeated, and then a second initialization bit and a second start bit of a predetermined bit are followed by a second bit of a predetermined bit predetermined for the information of the character length, the parity bit and the stop bit in the data communication. An initialization signal transmitting means for transmitting an initialization signal is provided, and the receiving station measures the time of 1 or 0 of the first initialization signal received from the transmitting station before starting data reception. The baud rate of the transmitting station is determined and set as its own baud rate, and the character length, parity bit and stop bit of the transmitting station are determined from the second initialization signal. Each character length of the station, but with the format setting means for setting a parity bit and a stop bit.

[0008]

In the start-stop synchronous data communication apparatus configured as described above, after the transmitting station and the receiving station are in the ready state, the first initial for setting the baud rate in an arbitrary start-stop synchronous format from the transmitting station. Then, the receiving station determines the baud rate of the transmitting station from the received initialization signal for setting the baud rate and sets the same baud rate for itself. Next, the transmitting station transmits a second initialization signal for setting the character length, parity bit, and stop bit, and the receiving station judges the character length, parity bit, and stop bit of the transmitting station from the received initialization signal, By setting the same character length, parity bit, and stop bit in the station as well, the work of the user inputting the asynchronous format can be eliminated.

[0009]

EXAMPLES Example 1. The configuration of the asynchronous data communication apparatus according to the first embodiment of the present invention is the same as that of the conventional FIG.
The contents of the processor processing of the first embodiment will be described according to the flowchart of FIG. In the figure, ST21 is a transmission station communication start time determination process, ST22 is a baud rate setting initialization signal transmission process, and ST23 is a character length, parity bit, stop bit setting initialization signal transmission process. It is a series of processing contents for automatically sending the format information from the transmitting station to the receiving station. Further, ST24 is a receiving station communication start timing determination process, ST25
Is a baud rate setting process, and ST26 is a character length, parity bit, and stop bit setting process, which is a series of processing contents in which the receiving station automatically sets the format based on a series of signals from the transmitting station.

Next, the operation will be described. As a premise,
It is necessary to input an arbitrary start-stop synchronization format (baud rate, character length, parity bit, stop bit) using the input device 1 and set it in the communication IC 5, but this processing procedure is the same as in the conventional case. is there. Then, it is confirmed by the transmitting station communication start timing determining process ST21 and the receiving station communication start timing determining process ST24 that the respective stations are in the communicable state. Next, in the baud rate setting initialization signal transmission process ST22, the transmitting station first transmits the first initialization signal for baud rate setting in the format already set in the communication IC 5 of the own station. The initialization signal to be transmitted at this time starts from the first start bit, and is followed by a pattern signal of 101010 ... And an arbitrary parity bit and stop bit. In the baud rate setting process ST25, the receiving station 10101010 after the start bit of the transmitted pattern signal.
By sampling 7 bits of 1 and measuring the time of these 1 or 0 periods, the baud rate of the transmitting station is judged and the same baud rate is set in the communication IC 5 of the own station.

Next, the transmitting station transmits the initialization signal for setting the character length, parity bit and stop bit ST23.
At 2, the second initialization signal is transmitted with the character length, the parity bit, and the stop bit already set in the communication IC 5 of the own station. The initialization signal transmitted at this time is 7 bits after the second start bit and represents the type of character length, parity bit, and stop bit. The receiving station determines the character length, parity bit, and stop bit type of the transmitting station from the initialization signal transmitted in the character length, parity bit, and stop bit setting processing ST26, and sets the same in the communication IC 5 of its own station. I do. By performing such processing, the same format as the format set in the transmitting station is automatically set in the receiving station. When the above format automatic setting process ends, the original data communication process starts.

Example 2. Although the first and second initialization signals are both 7-bit signals in the first embodiment, this is because the standard interface RS-232C is taken into consideration. It is not limited to.

Embodiment 3. In addition, in the first embodiment, the second
Although the information of the character length, the parity bit and the stop bit of the asynchronous format is sent by the initialization signal of, the other information may be sent in addition to these.

Example 4. In addition, in the above-mentioned first embodiment, as shown in FIG.
Although the processing shown in (1) is executed by the processor 3, it may be executed by the communication IC 5.

Example 5. Furthermore, in the above-mentioned Example 1, the first
Although the second initialization signal and the second initialization signal are each transmitted once, in order to improve reliability, it may be preliminarily arranged between the two stations to be transmitted a plurality of times. Further, in the above-described first embodiment, both stations perform each process continuously after the terminal ready, but a certain time interval is inserted between each process, and after the terminal ready, the two stations are synchronized. Alternatively, the process may be advanced.

Example 6. In the above-described first embodiment, both stations are configured to include the input device 1 and the digital input circuit 2. However, when the system according to the present invention is adopted, the input device 1 and the digital input circuit 2 are omitted on the receiving station side. Is possible.

[0017]

As described above, according to the present invention, the transmitting station is provided with the initialization signal transmitting means for transmitting the predetermined first and second initialization signals, and the receiving station is provided with the initialization signal. Since it has a format setting means to set the format of its own station, it is possible to always set the format of both stations necessary for start-stop synchronous data communication from only one station, and change the format setting. Also in this case, the processing content becomes simple.

[Brief description of drawings]

FIG. 1 is a flowchart showing a processing operation of an asynchronous communication data communication apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of an asynchronous data communication device.

FIG. 3 is a flowchart showing a processing operation of a conventional start-stop synchronous data communication device.

[Explanation of symbols]

1 Input device 3 Processor 5 Communication IC 6 Transmitting station device 7 Receiving station device 8 Transmission line ST21 Transmitting station communication start timing judgment process ST22 Baud rate setting initialization signal transmission process ST23 Character length, parity bit, stop bit setting initialization Signal transmission processing ST24 Reception station communication start time determination processing ST25 Baud rate setting processing ST26 Character length, parity bit, stop bit setting processing

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Claims (1)

[Claims] 1. An apparatus for transmitting and receiving data between a transmitting station and a receiving station by an asynchronous method based on a predetermined format, wherein the transmitting station has a first , A first initialization signal of a predetermined bit that repeats 1, 0, ..., And a second start bit, followed by a character length in the data communication,
Initialization signal transmitting means for transmitting a second initialization signal of a predetermined bit determined in advance for the information of the parity bit and the stop bit is provided, and the receiving station is provided with the transmitting station before starting data reception. The time of 1 or 0 of the first initialization signal received from is measured to determine the baud rate of the transmitting station and set as the baud rate of the own station, and the character of the transmitting station is determined from the second initialization signal. A start-stop synchronous data communication device comprising format setting means for determining a length, a parity bit and a stop bit and setting the character length, parity bit and stop bit of the local station, respectively.