JP2001325216A - Communication system switching device and communication system switching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system switching device for accelerating a data transfer speed and easily switching a synchronous communication mode and an asynchronous communication mode by using a CPU provided with a serial interface coping with both of a synchronous communication system and an asynchronous communication system. SOLUTION: This communication switching device 10 is provided with a setting part 13 for performing initialization, a control part 14 for switching the synchronous communication mode and the asynchronous communication mode and performing communication by either one of the communication modes and a counter 16 for counting the number of the pulse signals of a fixed cycle transmitted from a controller 20 at the time of performing data communication by the synchronous communication system. The communication mode of the control part 14 is set to the asynchronous communication mode by the setting part 13 at the time of activation and the communication mode of the control part 14 is switched to the synchronous communication mode when the prescribed number of pulses are detected by the counter 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system switching device for switching between a synchronous communication system and an asynchronous communication system, and more particularly to a data communication system using a pulse signal of the synchronous communication data system. The present invention relates to a communication system switching device that performs system switching.

[0002]

2. Description of the Related Art Conventionally, devices such as a cassette deck, an MD player and a CD player (hereinafter referred to as non-control devices) generally employ a synchronous communication system using a serial transmission system (hereinafter referred to as a serial transmission system). When these non-control devices are controlled by an external control device such as a key controller, as shown in FIG. 6, the non-control devices are provided with a data receiving unit 1, a data transmitting unit 2, and a clock signal for synchronizing. A communication device 4 including an input unit 3 is incorporated, and data is transmitted and controlled by an external control device 6 including a data receiving unit 1, a data transmitting unit 2, and a clock signal transmitting unit 5. ing.

On the other hand, control devices such as personal computers (hereinafter referred to as personal computers) which perform data communication by an asynchronous communication system have been also used to control these non-control devices. A method of data communication at the time is disclosed in Japanese Patent Laid-Open No. 9-698.
No. 49 is known.

As shown in FIG. 7, this communication method is incorporated between a non-control device and a communication device 7 for performing data communication by a synchronous communication system and a control device 8 for performing data communication by an asynchronous communication system. A communication system converter 9 for mutually converting synchronous communication data and asynchronous communication data. When an asynchronous communication start character signal is input from the control device 8 to the communication system converter 9, the communication system converter 9 The program stored inside is started, and the received asynchronous communication data is decoded into synchronous communication data,
This is performed by outputting the synchronous communication data to the communication device 7. Similarly, the synchronous communication data input from the communication device 7 is converted to asynchronous communication data and output to the control device 8 to be transmitted.

Recently, a central processing unit (hereinafter referred to as a CPU) having a serial interface and capable of directly communicating by switching the communication mode between synchronous communication data and asynchronous communication data is also inexpensive. Become
This CPU has been incorporated in a communication device to perform communication.

[0006]

However, in the method of performing the conversion between the synchronous communication and the asynchronous communication by the program, the input asynchronous communication data is converted one by one. Conversion takes a long time, and the data transfer speed is reduced.

Further, a C interface having a serial interface compatible with both the synchronous communication system and the asynchronous communication system
In the case of using a PU, a chip select port for switching between a synchronous communication system and an asynchronous communication system must be provided. The man-hour for changing the resistance has to be changed, and the quality of the substrate has deteriorated. Further, it is necessary to provide a circuit, a switch, and the like for switching the communication system, and the circuit of the board on which the CPU is mounted has become complicated.

The present invention uses a CPU having a serial interface compatible with both the synchronous communication system and the asynchronous communication system, solves the problem of low data transfer speed, and provides a circuit and a switch for switching the communication system. It is another object of the present invention to provide a communication system switching device for easily switching between a synchronous communication mode and an asynchronous communication mode.

[0009]

According to a first aspect of the present invention, there is provided a communication system switching apparatus for performing communication by at least one of a synchronous communication system and an asynchronous communication system. Communication means, a pulse signal detection means for detecting a pulse signal for obtaining synchronization of the data of the synchronization method, a counter for counting the pulse signal, and a setting means for setting the communication means to the asynchronous communication method When the communication unit is set to the asynchronous communication system by the setting unit, when the counter detects a predetermined number of the pulse signals, the communication unit is switched to the synchronous system. It has a configuration.

With this configuration, the asynchronous communication mode can be set by the setting means, and when the synchronous communication mode data is input in the asynchronous communication mode, the pulse signal of the synchronous communication mode data is input. Can be detected, so that the asynchronous communication mode can be easily switched to the synchronous communication mode, and communication can be performed in either communication mode.

In addition, communication can be performed by switching the communication mode of the communication means without converting communication data from synchronous communication data to asynchronous communication data, thereby performing data communication with an improved transfer speed. be able to.

Further, since the switching of the communication mode is controlled only by switching to the synchronous communication mode in the asynchronous communication mode, the switching control of the communication mode can be facilitated without providing an additional circuit. Operation can be stabilized.

According to a second aspect of the present invention, there is provided a communication system switching apparatus according to the first aspect, wherein the counter detects a change in the level value of the pulse signal in the first aspect of the invention. It has a configuration for detecting the number of pulse signals.

According to this configuration, a change in the level value of the pulse signal can be counted, so that a predetermined number of pulse signals can be detected.

According to a third aspect of the present invention, there is provided a communication system switching device according to the first aspect, wherein the counter detects a level value of the pulse signal at regular time intervals. It has a configuration for detecting the number of pulse signals.

With this configuration, the level value of the pulse signal can be detected at regular intervals, so that a predetermined number of pulse signals can be detected.

In order to achieve the above object, a communication method switching method according to a fourth aspect of the present invention includes a setting step of setting communication means to perform data communication by an asynchronous communication method, and a step of setting the communication means by the setting step. Detecting the pulse signal for obtaining the synchronization of the data of the synchronous communication system when the asynchronous communication system is set, and counting the number of the detected pulse signal, the detection step, When a predetermined number of the pulse signals are detected in the step, the communication means is switched to perform the data communication by the synchronous communication method.

According to this configuration, the asynchronous communication mode can be set by the setting means. When the asynchronous communication mode is set and the data of the synchronous communication system is input, the pulse signal included in the data of the synchronous communication system is set. Can be detected, so that the asynchronous communication mode can be easily switched to the synchronous communication mode, and communication can be performed in either communication mode.

Further, communication can be performed by switching the communication mode of the communication means without converting communication data from synchronous communication data to asynchronous communication data, thereby performing data communication with an improved transfer speed. be able to.

Further, since the switching of the communication mode is controlled only by switching to the synchronous communication mode in the asynchronous communication mode, the switching control of the communication mode can be facilitated without providing an additional circuit. Operation can be stabilized.

[0021]

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

FIGS. 1 to 5 show an embodiment of a communication system switching apparatus and a communication system switching method according to the present invention.
It is applied to communication devices such as microcomputers incorporated in non-control devices such as MD players, CD players, and cassette decks, or to a control method in which these non-control devices are externally controlled by an external controller and a personal computer via a communication system switching device. You.

First, the configuration will be described.

For example, as shown in FIGS. 1 and 2, a communication mode switching device 10 incorporated in an MD player as a microcomputer unit and performing communication by a serial transmission system outputs data from a data transmission unit 21 of control devices 20 and 30. A data receiving unit 11 for receiving the communication data, a data transmitting unit 12 for transmitting communication data to the data receiving unit 22 of the control devices 20 and 30,
A setting unit 13 for performing initial setting, and a control unit 14 for processing the data received by the data receiving unit 11 and transmitting the processed data to the control devices 20 and 30 via the data transmitting unit 12, The unit 13 and the control unit 14 constitute a setting unit and a communication unit of the present invention.

FIG. 1 is a system diagram of a control device 20 for performing data communication by a synchronous communication system and a communication system switching device 10 connected to the control device 20. The clock signal transmitted from the clock signal transmission unit 23 of the control device 20 is supplied to a clock signal receiving unit 15 for receiving a pulse signal of a predetermined period, that is, a clock signal receiving unit 15 for receiving a pulse signal of a predetermined period. A signal is to be input. This clock signal receiving section 15 constitutes a pulse signal detecting means of the present invention.

FIG. 2 is a system diagram of a control device 30 for performing data communication by the asynchronous communication method and a communication method switching device 10 connected to the control device 30. The signal receiving unit 15 and the counter 16 are not connected to the control device 30 unlike FIG.

When communication is performed by the asynchronous communication method, as shown in FIG. 2, both the clock signal receiving unit 15 and the counter 16 are fixed to a constant level value (eg, Hi) by a pull-up resistor. It does not change with. On the other hand, when the data for synchronous communication is output from the control device 20, a pulse signal appears on the counter 16 as shown in FIG. As a result, the clock signal receiving unit
The pulse signal can be detected in the counter 15 and the counter 16.

The counter 16 detects the input pulse signal, and when a predetermined number of pulse signals are detected, outputs a signal indicating that the pulse signal has been detected (hereinafter, referred to as a detection signal) to the control unit 14. It has become.

The counter 16 is configured by hardware so that a pulse signal transmitted at a high speed can be received without being missed.

The setting unit 13 has a memory (not shown), stores setting information set by the initial setting in this memory, and, based on this information, a communication method of the control unit 14 (hereinafter referred to as a communication mode). Is set.

Normally, in the initial setting, the control unit 14 processes data of the asynchronous communication system (hereinafter, referred to as asynchronous communication mode).
Therefore, when the communication mode switching device 10 is started, the control unit 14 is always set to the asynchronous communication mode.

The control unit 14 has a central processing unit (hereinafter referred to as C
PU), and the CPU performs data processing.

The control unit 14 processes synchronous synchronous data (hereinafter referred to as a synchronous communication mode) and operates in an asynchronous communication mode based on a detection signal output from the counter 16 or based on an instruction from the setting unit 13. One of the communication modes is set.

The control unit 14 analyzes the communication data received by the data receiving unit 11, outputs data to each processing unit (not shown) of the MD player, and controls each processing unit. Data from each processing unit of the MD player (not shown) is output to the control devices 20 and 30 via the data transmission unit 12.

When outputting the communication data, the control unit 14
When set to synchronous communication mode, by synchronous communication method, when set to asynchronous communication mode,
Data is transmitted by an asynchronous communication method.

When the communication mode of the control unit 14 is the synchronous communication mode, the control unit 14 synchronizes the clock signal of the internal operation based on the clock frequency of the control device 20 received by the clock signal data reception unit 14. , For transmitting and receiving data.

As described above, when the control device 20 outputs the data of the asynchronous communication system, it can respond in the initial setting state, and when the control device 20 outputs the data of the synchronous communication system, the counter 16 outputs a pulse to the counter 16. Since the signal is input, the communication mode of the control unit 14 is switched to the synchronous communication mode, and communication can be performed in the synchronous communication mode.

Next, the operation of switching the communication mode of the communication system switching device 10 will be described. Here, FIG. 3 is a flowchart showing this operation.

First, the communication mode switching device 10 is started, the communication mode of the control unit 14 is set to the asynchronous communication mode, and the input of a pulse signal is monitored by the counter 16 (step S1).

At this time, when the pulse signal has not been detected and the data of the asynchronous communication system is input, data communication is performed by the asynchronous communication system in this state.

When a pulse signal is detected in this state, it is determined whether a predetermined number of pulse signals have been detected (step S2). When a predetermined number of pulse signals are not detected, this determination is repeated and monitoring of the pulse signals is continued. When a predetermined number of pulse signals are detected, the following operation is performed.

First, a connection confirmation command composed of a predetermined number of bytes is input from the control device 20 to the control unit 14 via the data receiving unit 11, and the control unit 14 is set to the synchronous communication mode (step S3).

Next, a connection confirmation command composed of a predetermined number of bytes is again input from the control device 20 to the control unit 14 via the data input unit 11. When the second connection confirmation command is input, the control unit 14 transmits a status of a response to the connection confirmation command from the data transmission unit 12 (step S4).

Next, upon confirming this response, the control device 20 starts transmitting data to the communication system switching device 10 (step S5). Note that the control device 20 continues to transmit the connection confirmation command until the communication mode switching device 10 returns a response status.

Finally, when the control unit 14 detects the reception of data, the monitoring of the counter 16 is terminated (Step S).
6), end this operation.

As described above, switching between the synchronous communication mode and the asynchronous communication mode is performed. When the communication mode is switched by the synchronous communication method, the confirmation processing for establishing the synchronous communication (step S3, step S4, step S5) is performed by the connection confirmation command. When switching from the asynchronous communication mode to the synchronous communication mode, the command output from the control device 30 is not invalidated.

As described above, according to the present embodiment, the control unit 14 of the communication system switching apparatus 10
Is set to the asynchronous communication mode, and when data is transmitted from the control device 20 in the synchronous communication mode, the predetermined number of pulse signals can be detected by the counter 16, so that the asynchronous communication data and the synchronous communication data are It is possible to recognize which one is, and the processing operation of the control unit 14 can be switched. As a result, communication can be performed in both the synchronous communication mode and the asynchronous communication mode, and the communication method switching device 10 can be easily and accurately operated.

Further, since the data can be directly communicated without converting the communication data from the synchronous communication data to the asynchronous communication data, the data communication with a high transfer rate can be performed.

The switching between the synchronous communication mode and the asynchronous communication mode is performed by restarting the communication system switching device 10. Usually, the communication mode is set by setting the communication mode of the control device 20 to a fixed one. Has been
Once done, there is no need to do it during the operation. if,
When switching from the synchronous communication mode to the asynchronous communication mode is required, the control device 20 is also reconnected to a device having a different communication mode. Therefore, as described above, the control can be sufficiently performed by restarting the communication method switching device 10. It has become. In addition, by restarting the communication system switching device 10 in this manner, the configuration and the algorithm can be simplified, and unstable operations in the device and the system can be eliminated.

In this embodiment, the counter is provided inside the communication system switching device 10, but as shown in FIGS.
It may be arranged outside the device.

In this case, the detection signal output from the counter 40 is input to a detection signal input section 41 of the communication system switching device 10, and the detection signal input section 41 outputs the detection signal to the control section 14 Output.

In the present embodiment, the number of pulse signals of the counter 16 is detected by detecting an edge interrupt of the input pulse signal, that is, detecting a change in the level value of the input pulse signal, or a timer interrupt, that is, by detecting the CPU interrupt.
The number of pulse signals may be detected by detecting the level value of the input pulse signal at regular intervals based on the timer.

In this case, even if it does not have the counter 16 for detecting the input pulse signal, it is possible to have a configuration capable of detecting the level change of the pulse signal or the level value of the pulse signal at regular time intervals. I just need.

[0054]

As described above, the communication mode switching device of the present invention is set to the asynchronous communication mode by the initial setting, and is set to the asynchronous communication mode when data is input in the synchronous communication mode. Communication mode can be converted to a synchronous communication mode, so that communication can be performed in either the synchronous communication mode or the asynchronous communication mode, and communication data is converted from synchronous communication data to asynchronous communication data. Thus, high-speed data communication can be performed.

[Brief description of the drawings]

FIG. 1 is a system diagram for explaining a synchronous communication system in an embodiment of a communication system switching device according to the present invention.

FIG. 2 is a system diagram for explaining an asynchronous communication system in one embodiment of the communication system switching device according to the present invention.

FIG. 3 is a flowchart illustrating a principle of switching operation between synchronous communication and asynchronous communication according to the embodiment;

FIG. 4 is a system diagram for explaining a synchronous communication system when a counter according to one embodiment is provided outside.

FIG. 5 is a system diagram for explaining an asynchronous communication system when a counter is provided outside in one embodiment.

FIG. 6 is a system diagram for explaining a communication device performed by a conventional synchronous communication method.

FIG. 7 is a diagram for explaining a conventional communication method for performing data conversion between a synchronous communication method and an asynchronous communication method.

[Explanation of symbols]

 10 Communication mode switching device 13 Setting section (setting means) 14 Control section (communication means) 15 Clock signal receiving section (pulse signal detecting means) 16, 30 counter

Claims (4)

[Claims] A communication means for performing data communication by at least one of a synchronous communication method and an asynchronous communication method, and a pulse signal detection for detecting a pulse signal for obtaining synchronization of data of the synchronous communication method Means, a counter for counting the pulse signal, and a setting means for setting the communication means to the asynchronous communication method, when the communication means is set to the asynchronous communication method by the setting means, A communication system switching device, wherein when the counter detects a predetermined number of the pulse signals, the communication unit is switched to the synchronous communication system. 2. The communication system switching device according to claim 1, wherein the counter detects the number of the pulse signals by detecting a change in the level value of the pulse signal. 3. The communication system switching device according to claim 1, wherein the counter detects the number of the pulse signals by detecting a level value of the pulse signal at regular time intervals. 4. A setting step of setting the communication means to perform data communication by the asynchronous communication method, and, when the communication means is set to the asynchronous communication method by the setting step, data of the synchronous communication method is provided. Detecting a pulse signal for synchronizing, and detecting the number of the detected pulse signals, including a detecting step, when the detection step detects a predetermined number of the pulse signals, the communication means, A data communication system switching method, wherein the data communication is switched so as to be performed by a synchronous communication system.