JP2005295466A - Communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication method capable of preventing a communication collision in half duplex communication.
A transmission right acquisition time zone in which a data transmission right can be acquired for each device that transmits and receives data by half-duplex communication does not overlap each other for each cycle of a power supply synchronization signal. It is set in advance as follows. Then, each device starts a timer every time the base point of the period of the power supply synchronization signal is detected (step S201), and the elapsed time of the timer falls within the transmission right acquisition time zone of the own device (step S206). After acquiring the transmission right (step S207), data transmission is executed.
[Selection] Figure 2

Description

  The present invention relates to a communication method for performing communication so that communication collision does not occur in half-duplex communication between devices.

  Normally, when designing a system that performs data communication between devices, it is necessary to design in consideration of the direction of data transmission. That is, if each device transmits data simultaneously on one communication transmission path, a data collision occurs on the communication transmission path and normal communication cannot be performed. In order to prevent data from colliding during communication, an arrangement (communication method) such as determining a communication direction in advance is required. Communication systems are generally classified into unidirectional communication systems, half-duplex communication systems, and full-duplex communication systems.

  The unidirectional communication method is uniquely determined by the transmitting device and the receiving device, and the full-duplex communication method has independent transmission and reception communication transmission paths. For this reason, there is no data collision. However, these two communication methods have the advantage that data collision does not occur. On the other hand, the unidirectional communication method has the disadvantage that bidirectional communication is not possible. There is a disadvantage that the hardware configuration is separately required for transmission and reception, and is expensive.

  The half-duplex communication method is a method in which transmission / reception hardware (device) uses one communication transmission line while switching between transmission processing and reception processing. Each device can perform bidirectional data communication, but cannot perform transmission processing and reception processing at the same time. Also, since a single communication transmission path is shared by each device, if one device transmits data while another device transmits data, a data collision occurs and normal communication is performed. Cannot be performed.

  In the field of embedded device systems, when designing a system or hardware / LSI (for example, a microcomputer) capable of bidirectional communication, the circuit related to transmission and reception is simpler than the full-duplex communication method. A half-duplex communication method is often used because it can be made inexpensively.

  When communication is performed by the half-duplex communication method, there is a communication collision problem described above, and thus a half-duplex communication system including a mechanism for detecting a data collision has been conventionally proposed (for example, Patent Document 1). reference.). In addition, a device that prevents data collision using a dedicated hardware configuration has been proposed (see, for example, Patent Document 2).

  However, in a conventional half-duplex communication system that includes a collision detector and performs collision determination, data transmission interruption, data content saving, data retransmission processing, etc. when a collision is detected, both in hardware and software Even a complicated configuration was required.

  As another method, there is a method of performing communication control by providing a control signal line for a transmission prohibition signal or a transmission request signal in addition to a communication transmission line. However, an extra dedicated signal line is required and software is used. In the case of processing, there still remains a problem that the other party's transmission cannot be completely prohibited.

Moreover, according to the full-duplex communication method, the problem of collision is eliminated, but there is a problem in terms of cost compared to hardware of the half-duplex communication method.
In addition, there is a method for preventing collision by adding dedicated hardware, but there is also a cost problem.
JP 2002-502563 A (page 7-14, FIG. 2) Japanese Patent Laid-Open No. 9-321737 (page 5-6, FIGS. 1 and 12)

  In view of the above problems, the present invention shows transmission right acquisition time zones in which data transmission right can be acquired for each device that transmits and receives data by a predetermined communication method, as shown in FIGS. As described above, it is set in advance so that they do not overlap each other with reference to the period base point of the periodic signal, and each device transmits transmission data after acquiring the transmission right in the transmission right acquisition time zone of its own device. Therefore, it aims at providing the communication method which can prevent the communication collision in half-duplex communication.

  In the communication method according to claim 1 of the present invention, in a communication system in which communication is performed between a plurality of devices, each of the devices has a transmission right acquisition time zone in which acquisition of data transmission right is possible. Communication that is preset in a range that does not overlap each other for each period of a periodic signal, and each of the devices transmits transmission data after acquiring the transmission right in the transmission right acquisition time zone of the own device A method in which each of the devices detects a base point of a period from the periodic signal input to each of the devices, and measures an elapsed time based on the detected base point A timer starting step of starting a timer, a determination step of determining whether or not another device has already acquired the transmission right, and when the other device has not acquired the transmission right, Transmission right acquisition time zone When the elapsed time of the timer is within the range of the transmission right acquisition time zone of the own device, a transmission right acquisition command is issued to another device to determine the transmission right. And a transmission right acquisition step to acquire.

  The communication method according to claim 2 of the present invention is the communication method according to claim 1, further comprising a transmission right releasing step of releasing the transmission right when transmission of transmission data is completed. .

  A communication method according to claim 3 of the present invention is the communication method according to claim 1 or 2, wherein the periodic signal is a power supply synchronization signal generated from a commercial power supply. It is characterized by that.

  The communication method according to claim 4 of the present invention is the communication method according to any one of claims 1 to 3, wherein the device that has acquired the transmission right is set to each of the devices to other devices. The transmission right acquisition time zone of each of the devices can be arbitrarily changed by issuing a command for changing the transmission right acquisition time zone.

  The communication method according to claim 5 of the present invention is a communication system in which communication is performed between two devices. Are alternately set with reference to the base point of the period of the periodic signal, and each of the devices transmits the transmission data after acquiring the transmission right in the transmission right acquisition time zone of the own device. A determination step of determining whether each of the devices has already acquired the transmission right, and the other device has not acquired the transmission right, and the own device And a transmission right acquisition step of acquiring the transmission right by issuing a transmission right acquisition command to the other device in the transmission right acquisition time period.

  The communication method according to claim 6 of the present invention is the communication method according to claim 5, wherein the periodic signal has a period equal to or longer than a time required for issuing the transmission right acquisition command. It is a signal.

  A communication method according to claim 7 of the present invention is the communication method according to claim 5 or 6, wherein the transmission right acquisition time zone is a base point of the period of the periodic signal. It is determined whether or not the generation periods of two types of signals with different potential levels that are alternately generated based on the reference are assigned to each of the devices, and are within the transmission right acquisition time zone of the own device in the transmission right acquisition step. In this case, the generation period of the two kinds of signals is determined.

  The communication method according to claim 8 of the present invention is the communication method according to claim 7, wherein the two types of signals are a signal having a potential level of H level and a signal having a potential level of L level. Features.

  The communication method according to claim 9 of the present invention is the communication method according to claim 8, wherein each of the devices detects a rising edge of the H level signal and a falling edge of the L level signal. When determining whether or not it is the transmission right acquisition time zone of its own device in the transmission right acquisition step, the most recently detected edges are the rising edge of the H level signal and the L level signal. It is characterized by determining which one of the falling edges.

  A communication method according to claim 10 of the present invention is the communication method according to any one of claims 5 to 9, comprising a transmission right release step of releasing the transmission right when transmission of transmission data is completed. It is characterized by doing.

  The communication method according to claim 11 of the present invention is the communication method according to any one of claims 5 to 10, wherein the periodic signal is a power supply synchronization signal generated from a commercial power supply. It is characterized by that.

  In the communication method according to claim 12 of the present invention, in the communication system in which communication is performed between a plurality of devices, each of the devices includes an initial value of an identifier of the own device, an identifier of a transmitter capable device, and the When the transition order of identifiers of transmittable devices is set in advance, each of the devices matches the identifier of the own device and the identifier of the transmittable device, and there is transmission data in the own device, A communication method for acquiring transmission right of data and transmitting transmission data, wherein each of the devices determines whether or not another device has already acquired the transmission right; A second determination step of determining whether or not a base point of a period of a periodic signal input to each of the devices is detected within a predetermined period when another device has not acquired the transmission right; And the base point is detected A third determination step for determining whether or not the identifier of the transmittable device and the identifier of the own device match, and the identifier of the transmittable device and the identifier of the own device match, and When there is no transmission data in the device, a setting step for setting the next identifier of the transmittable device in accordance with the transition order of the identifier of the transmittable device for each of the devices, and the identifier of the transmittable device A transmission right acquisition step of issuing a transmission right acquisition command to another device and acquiring the transmission right when the identifier of the device matches and the transmission data exists in the own device; In each of the devices, a transmission right acquisition time zone in which the identifier of the device capable of transmission matches the identifier of the device itself and the transmission right can be acquired is a unit of one period of the periodic signal. Assigned as And wherein the door.

  A communication method according to claim 13 of the present invention is the communication method according to claim 12, wherein one of the devices is predetermined as a master device, and the master device is the own device or other device. By issuing a command for changing the transition order of the identifiers of the transmittable devices in response to a request from the device, the transition order of the identifiers of the transmittable devices can be arbitrarily changed.

  A communication method according to claim 14 of the present invention is the communication method according to claim 12 or 13, further comprising a transmission right releasing step of releasing the transmission right when transmission of transmission data is completed. It is characterized by doing.

  A communication method according to claim 15 of the present invention is the communication method according to any one of claims 12 to 14, wherein the periodic signal is a power supply synchronization signal generated from a commercial power supply. It is characterized by that.

  A communication method according to a sixteenth aspect of the present invention is the communication method according to any one of the first to fourth aspects, wherein the transmission right acquisition time zone is already set, Each additional device added to the communication system has an additional device transmission time zone in which the additional device can transmit transmission data to a device for which the transmission right acquisition time zone has already been set. The transmission right acquisition time zone is set in advance within a range that does not overlap with the transmission right acquisition time zone for each cycle of the signal, and when the additional device detects the additional device transmission time zone, the transmission right acquisition time zone is already set. A transmission right acquisition time zone provision requesting step for requesting the device to provide the transmission right acquisition time zone; and obtaining the transmission right acquisition time zone from a device for which the transmission right acquisition time zone has already been set. machine A calculation step of calculating a new transmission right acquisition time zone, and when the additional device transmission time zone is detected, the new transmission right acquisition time zone for a device for which the transmission right acquisition time zone has already been set And a new transmission right acquisition time zone setting requesting step for requesting the setting of a new transmission right.

  The communication method according to claim 17 of the present invention is the communication method according to claim 16, wherein the device that has acquired the transmission right issues a command for changing an additional device transmission time zone to other devices. The additional device transmission time zone can be arbitrarily changed.

  According to the present invention, it is possible to configure a communication system in which communication collision does not occur even if inexpensive hardware for a half-duplex communication system is used. Therefore, there is an advantage that it is not necessary to add a special hardware function. In addition, since no communication collision occurs, complicated software processing for countermeasures against collision is not required, so that the embedded device system is effective in reducing ROM / RAM capacity and test man-hours.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an example of a communication system using a predetermined communication method in the present embodiment, and a plurality of devices (devices A, B, and C) are connected to one communication transmission path (UART communication line). 1 shows a communication system in which each device issues a predetermined command at an arbitrary timing and executes data transmission / reception processing according to the command by a predetermined communication method. According to the communication method of the present embodiment, as will be described later, since only the device that has acquired the right to transmit data can execute the data transmission process, the collision of data (including commands) on the communication transmission line ( Occurrence of 'communication collision)' can be avoided.

Device A, device B, and device C perform UART communication using a half-duplex communication method, and each have AC zero-cross detection means.
The AC zero-cross detection means is means for detecting a voltage 0 [V] of a commercial power waveform (West Japan: 60 Hz, East Japan: 50 Hz). The power supply synchronization signal is generated in synchronization with the detection of the voltage 0 [V]. This power supply synchronization signal is widely used in home appliances, for example, as a reference signal for ON / OFF control of a triac or relay.

  Since device A, device B, and device C are supplied with power from the same commercial power line, the same commercial power waveform is input to each. Therefore, the power supply synchronization signals (periodic signals) input to the devices A, B, and C match, and the devices A, B, and C can obtain the same synchronization timing.

(Embodiment 1)
Hereinafter, the communication method according to the first embodiment will be described with reference to FIGS.
However, here, for ease of explanation, it is assumed that only two devices, device A and device B, communicate.

FIG. 2 is a diagram showing a flowchart of data transmission / reception processing of each device in the first embodiment.
FIG. 3 is a conceptual diagram of a transmission right acquisition time zone of each device according to the first embodiment. As shown in FIG. 3, the transmission right acquisition time zones of the respective devices are set in advance so as not to overlap each other for each cycle of the power supply synchronization signal.

  In the communication methods according to the first to sixth embodiments, each device has a transmission right specific to its own device that does not overlap with other devices set with reference to the base point of the cycle of the power supply synchronization signal (power supply synchronization signal detection point). In the acquisition time period, the transmission right can be acquired only when the other device has not acquired the transmission right, and the transmission data can be transmitted only after the transmission right is acquired. The transmission right can be acquired by issuing a transmission right acquisition command. Therefore, while an arbitrary device has acquired the transmission right, other devices cannot transmit data, so that data does not collide on the communication transmission path. In addition, since the transmission right acquisition command is issued only in the transmission right acquisition time zone unique to each device, the transmission right acquisition command does not collide on the communication transmission path.

Hereinafter, the communication method in the first embodiment will be described using the device A. The device A transmits / receives data by repeating the data transmission / reception processing operation shown in FIG.
When the device A detects the base point (voltage synchronization signal detection point) of the cycle from the voltage synchronization signal (step S200: base point detection step), a timer (timer mechanism; counting) is used to count the elapsed time from the base point of the cycle. This is the same for a container.) (Step S201: Timer activation step). As described above, in the communication method according to the first embodiment, each device starts the timer every time it detects the base point of the period of the voltage synchronization signal.

  Then, it is determined whether another device B has already acquired the transmission right (step S202: determination step). In addition, while the base point of the period of a voltage synchronous signal is not detected in the starting point (START) of this processing flow, it will be performed by the process of this step S202.

  If another device B has acquired the transmission right, the receiving process is executed (step S208), and this process flow is restarted (START). Therefore, while the other device B has acquired the transmission right, the device A executes only the reception process (step S208).

If the other device B has not acquired the transmission right, it is determined whether or not the own device A has already acquired the transmission right (step S203).
If the own device A has not acquired the transmission right, it is determined whether or not there is data to be transmitted (step S204). If there is no data to be transmitted, reception processing is executed (step S208). This processing flow is started again (START).

  When there is data to be transmitted, the setting value of the transmission right acquisition time zone of the own device A is acquired from the management table of the own device A (step S205), and compared with the elapsed time of the timer activated in step S201. Then, it is determined whether or not the elapsed time is within the transmission right acquisition time zone (step S206).

  As a result, if it is not within the range, the reception process is executed (step S208) and this processing flow is started again (START) until the elapsed time of the timer falls within the range of the transmission right acquisition time zone of the own device A. This processing flow (steps S200 to S206 and step S208) is repeated.

If it is within the range, a transmission right acquisition command is issued to acquire the transmission right (step S207), and this processing flow is restarted (START).
In the first embodiment, the transmission right acquisition process includes steps S205 to S207. The transmission right acquisition time zone needs to have at least a time width in which the transmission right acquisition command issuance process can be executed.

  While acquiring the transmission right, the device A repeats the transmission process in step S211 until it is determined in step S209 that transmission of transmission data has been completed. That is, the processes of step S200 to step S203, step S209, and step S211 are repeated.

Then, after transmitting all the transmission data, a process for releasing the transmission right is executed (step S210: transmission right releasing step), and this processing flow is started again (START).
The same processing is performed for the device B, but by setting the transmission right acquisition time zone of the device B so as not to overlap with the device A, a transmission right acquisition command collision on the communication transmission path is avoided. It becomes possible to do.

  Here, as an example of setting the transmission right acquisition time zone of each device, when the commercial power supply frequency is 60 Hz, the cycle of the power supply synchronization signal is about 8.3 ms, so the power supply synchronization signal detection point (the base point of the cycle) 1 to 3 ms is set for device A, and 5 to 7 ms is set for device B. However, when set in this way, the device A must be able to execute the processing of step S200 to step S207 at least 1 to 3 ms from the power synchronization signal detection point.

  In addition, although the example by two apparatuses of apparatus A and apparatus B was given, by predetermining to each apparatus so that a transmission right acquisition time zone may not overlap and be within one cycle of a power supply synchronization signal, The same can be applied to the case of three or more devices.

(Embodiment 2)
Hereinafter, the communication method according to the second embodiment will be described with reference to FIGS.
However, here, for ease of explanation, it is assumed that only two devices, device A and device B, communicate, but the same applies to the case where communication is performed by three or more devices.

  FIG. 4 is a conceptual diagram of a transmission right acquisition time zone of each device according to the second embodiment. As shown in FIG. 4, the transmission right acquisition time zone of each device is different from the communication method in the first embodiment in that it can be changed by a special command (command for changing the transmission right acquisition time zone).

  The special command is transmitted by a device that has acquired the transmission right. That is, when the device that has acquired the transmission right transmits a special command, the setting value of the transmission right acquisition time zone of other devices is rewritten.

  While a certain device has acquired the transmission right, the other device performs only the reception process (transition from step S202 to step S208), and a comparison determination process between the transmission right acquisition time zone and the elapsed time of the timer ( Since step S206) is not executed, inconsistency due to the change in the transmission right acquisition time zone does not occur.

  As shown in the second embodiment, by rewriting the setting value of the transmission right acquisition time zone of each device, the priority of transmission right acquisition within one cycle of the power synchronization signal can be changed as shown in FIG. It becomes possible.

  In addition, as shown in FIG. 4, the allocation of each device is performed when the time required for transmitting the transmission right acquisition command varies depending on the device, such as transmission with additional information added to the transmission information for acquiring the transmission right. Rewriting to optimize the time width (time width of the transmission right acquisition time zone) is also possible.

(Embodiment 3)
Hereinafter, the communication method according to the third embodiment will be described with reference to FIGS.
However, the communication method in Embodiment 3 is limited to the case where two devices communicate.

FIG. 5 is a diagram showing a flowchart of data transmission / reception processing of each device in the third embodiment.
FIG. 6 is a conceptual diagram of a transmission right acquisition time zone of each device according to the third embodiment. Here, as shown in FIG. 6, a signal having a potential level of H level and a signal having a potential level of L level, which are alternately generated at each power synchronization signal detection point, are used. For example, as a transmission right acquisition time zone, the generation period of the H level signal is allocated to the device A, and the generation period of the L level signal is allocated to the device B.

  Generation of the H / L level signal from the power supply synchronization signal can be realized by a conventional method such as generation by a function mounted on the AC zero cross detection circuit or generation by an external circuit.

  Hereinafter, the communication method in the third embodiment will be described using the device A. However, it is assumed that the device A is assigned an H level signal generation period and the device B is assigned an L level signal generation period as the transmission right acquisition time zone. The device A transmits and receives data by repeating the data transmission / reception processing operation shown in FIG.

First, the device A determines whether or not the other device B has already acquired the transmission right (step S500: determination step).
If the other device B has acquired the transmission right, a reception process is executed (step S505), and this process flow is restarted (START). Accordingly, while the other device B has acquired the transmission right, the device A executes only the reception process (step S505).

If the other device B has not acquired the transmission right, it is determined whether or not the own device A has already acquired the transmission right (step S501).
If the own device A has not acquired the transmission right, it is determined whether or not there is data to be transmitted (step S502). If there is no data to be transmitted, reception processing is executed (step S505). This processing flow is started again (START).

  If there is data to be transmitted, it is determined whether or not it is currently the period of the H level signal (the transmission right acquisition time zone of the own device A) (step S503). Whether or not it is the generation period of the H level signal can be determined by detecting the rising edge of the H level signal and the falling edge of the L level signal. That is, since the period from the detection of the rising edge of the H level signal to the detection of the falling edge of the L level signal is the generation period of the H level signal, was the most recent detection being the detection of the rising edge of the H level signal? Judgment can be made depending on whether

  As a result, when the falling edge of the L level signal is detected, the reception process is executed (step S505), and this processing flow is started again (START). This process is performed until the rising edge of the H level signal is detected. The flow (steps S500 to S503 and step 505) is repeated.

  If the rising edge detection of the H level signal is detected, it is the generation period of the H level signal, so a transmission right acquisition command is issued to acquire the transmission right (step S504), and this processing flow is restarted (START). .

  In the third embodiment, the transmission right acquisition process includes step S503 and step S504. Of course, at least one time period in which the transmission right acquisition command issuance process can be executed in one cycle of the power supply synchronization signal.

  While acquiring the transmission right, the device A repeats the transmission processing in step S508 until it is determined in step S506 that transmission of transmission data has been completed. That is, the process of step S500, step S501, step S506, and step S508 is repeated.

Then, after transmitting all the transmission data, processing for releasing the transmission right is executed (step S507: transmission right releasing step), and this processing flow is started again (START).
On the other hand, the same processing is performed for the device B. That is, since the generation period of the L level signal is assigned to the device B, the determination process in step S503 determines whether the determination process is the generation period of the L level signal, that is, the most recent detection is the L level signal generation period. The process is the same as that of the device A except that the process determines whether or not the falling edge has been detected.

The difference from the first embodiment is that a timer for measuring the elapsed time from the base point is unnecessary, and there is an advantage that timer resources can be saved.
The communication method according to the third embodiment only supports communication between two devices, and as shown in FIG. 6, transmission right acquisition time zones are alternately assigned to each power synchronization signal detection point. Therefore, even if an error occurs in the determination timing of edge detection in both devices, the error can be sufficiently absorbed. As an error in the determination timing, there may be a case where the processing time is occupied by another task and the start of this processing flow (START) is awaited.

  Here, an H level signal and an L level signal are used, but two types of signals having different potential levels may be used. For example, as described above, rising edges and falling edges of two types of signals are detected. Can be implemented.

  Further, for example, a potential level period may be detected by dividing a signal whose potential level switches at each base point of the period of the power supply synchronization signal by a threshold value.

  Further, if three or more potential levels are used, even when communication is performed between three or more devices, the same can be implemented. For example, by generating a signal in which the potential level repeats “H” → “M” → “L” at each power supply synchronization signal detection point, the present invention can be implemented with three devices.

(Embodiment 4)
Hereinafter, the communication method according to the fourth embodiment will be described with reference to FIGS.
Here, description will be made on the assumption that three devices, device A, device B, and device C, communicate.

FIG. 7 is a diagram illustrating a flowchart of data transmission / reception processing of each device according to the fourth embodiment.
FIG. 8 is a conceptual diagram of the transmission right acquisition time zone of each device in the fourth embodiment.

  Here, the ID (identifier) of the device A is “1”, the ID of the device B is “2”, the ID of the device C is “3”, and the master device is the device A with the smallest ID. The method of determining the master device does not depend on the ID, and may be determined by an external switch, for example.

  In addition, for each of the devices A, B, and C, the initial value of the ID of the transmittable device and the transition order of the ID of the transmittable device are set in advance together with the IDs. The device A, device B, and device C can acquire the transmission right when the ID of the own device and the ID of the current transmittable device match. It should be noted that all transition orders may be set as the ID transition order of transmittable devices, or only the ID to be transitioned next may be set.

  Hereinafter, the communication method according to the fourth embodiment will be described using device A (master device). The device A transmits / receives data by repeating the data transmission / reception processing operation shown in FIG.

First, the device A determines whether another device B or device C has already acquired the transmission right (step S700: first determination step).
If another device B or device C has acquired the transmission right, a reception process is executed (step S707), and this process flow is restarted (START). Therefore, while the other device B or device C acquires the transmission right, the device A executes only the reception process (step S707).

If the other devices B and C have not acquired the transmission right, it is determined whether or not the own device A has already acquired the transmission right (step S701).
If the own device A has not acquired the transmission right, it is determined whether or not the base point of the period of the power supply synchronization signal has been detected between the start of this processing flow (START) and this processing (predetermined period). (Step S702: Second determination step). Of course, the predetermined period is not limited to this.

  As a result, if it is not detected, the reception process is executed (step S707), the process flow is started again (START), and this process flow (steps S700 to S702, until the base point of the cycle is detected). Step S707) is repeated.

If it has been detected, it is determined whether or not the ID of the current transmittable device and the ID of the own device A match (step S703: third determination step).
As a result, if they do not match, the reception process is executed (step S707), and this process flow is started again (START). Therefore, if they do not match, the reception processing is performed up to at least the next base point.

  If there is a match, a determination is made as to whether there is data to be transmitted (step S704). If there is no data to be transmitted, the ID of the current transmittable device set in the management table of the own device is determined. The next ID set in advance is set, and the ID information of the next transmittable device is transmitted to the other devices B and C (step S706), and this processing flow is started again (START). The devices B and C that have received the ID information of the next transmittable device set the ID of the transmittable device set in the management table of the own device as the next ID.

Note that the transmission of the ID information of the next transmittable device is executed only by the device corresponding to the ID of the current transmittable device, so this transmission data collision does not occur on the communication transmission path.
If there is data to be transmitted, a transmission right acquisition command is issued to acquire the transmission right (step S705), and this processing flow is restarted (START).

In the fourth embodiment, the setting process includes steps S704 and S706, and the transmission right acquisition process includes steps S704 and S705.
Of course, at least one time period in which the transmission right acquisition command issuance process can be executed in one cycle of the power supply synchronization signal.

  The data received during the reception process in step S707 includes information on IDs of transmittable devices transmitted by the devices B and C. The received ID of the transmittable device is used for the determination process in step S703.

  While acquiring the transmission right, the device A repeats the transmission process of step S710 until it determines transmission completion of transmission data in step S708. That is, the process of step S700, step S701, step S708, and step S710 is repeated.

Then, after transmitting all the transmission data, processing for releasing the transmission right is executed (step S709: transmission right releasing step). This processing flow is started again (START).
The same processing is performed for the devices B and C.

  If the ID of the device A, which is the master device, is set in each device as the initial value of the ID of the device capable of transmission, the device A first executes the process of step S706 as the master device.

  As described above, according to the fourth embodiment, when the base point of the period of the power supply synchronization signal is detected in a predetermined period, it is determined whether the ID of the device capable of transmission matches the ID of the own device. As shown in FIG. 8, a transmission right acquisition time zone is assigned to each device in units of one cycle of the power supply synchronization signal.

Further, according to the fourth embodiment, it is possible to cope with communication of three or more devices.
Similarly to the third embodiment, even if an error occurs in the timing of whether or not the base point has been detected in each device (second determination step), the error can be sufficiently absorbed.

(Embodiment 5)
Hereinafter, the communication method according to the fifth embodiment will be described with reference to FIGS.
Here, description will be made on the assumption that three devices, device A, device B, and device C, communicate.

  FIG. 9 is a diagram showing a flowchart of data transmission / reception processing of devices B and C, that is, devices other than the master device in the fifth embodiment. However, the steps (steps) described in the fourth embodiment are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 10 is a conceptual diagram of the transmission right acquisition time zone of each device in the fifth embodiment. As shown in FIG. 10, the transmission order acquisition time zone transition order is different from the communication method according to the fourth embodiment in that it can be changed by changing the transmission order ID transition order.

Hereinafter, the communication method according to the fifth embodiment will be described focusing on the process of changing the transition order of IDs of transmittable devices.
When the devices B and C receive the ID information of the transmittable device in the reception process (step S707), they are stored in the management table (step S901). This information is read in step S902 and transmitted in step S706.

  Here, regarding the change of the transition order of the transmittable device IDs, only the master device can be instructed to prevent inconsistency. That is, transmission is possible when the master device A issues a command to change the ID transition order of devices that can be transmitted to the other devices B and C in response to a request from the own device A or other devices B and C. Change the transition order of device IDs.

When the devices B and C make a request for changing the transition order of the device IDs that can be transmitted (step S903), the devices B and C transmit the change request to the master device A (step S904).
Only the devices B and C other than the master device A execute the process for changing the transmission order of the device IDs that can be transmitted (steps S903 and S904). That is, the process except for step S903 and step S904 is the process flow of the master device A.

The master device A receives the change request information (step S707). If no inconsistency occurs, the master device A issues a transmission right acquisition command to acquire the transmission right (step S705).
A new transition order corresponding to the request is set in the own device, and information on the new transition order is transmitted to the other devices B and C (step S710).

  Even if the transition order set for each device is all transition orders, only the ID to be transitioned next (that is, the ID of the device that can acquire the transmission right next to the own device) is set. Even if it is a case, it can be implemented similarly. Of course, the master device A can also change the device itself.

  According to the fifth embodiment, for example, as shown in FIG. 10, when it is desired to increase the priority of transmission right acquisition for device C, device A → device C from the order of device A → device B → device C. → The priority can be changed to the order of device B.

(Embodiment 6)
Hereinafter, the communication method according to the sixth embodiment will be described with reference to FIGS. 11 and 12.
FIG. 11 is a diagram illustrating a flowchart of the device addition process of the additional device according to the sixth embodiment. This process is performed until the addition of the device is completed. After the addition is completed, the data transmission / reception process described in the first embodiment is executed.

  FIG. 12 is a conceptual diagram of a transmission right acquisition time zone and an additional device transmission time zone of each device in the sixth embodiment. Here, description will be made assuming that the device A and the device B are devices for which a transmission right acquisition time zone has already been set in this communication system (hereinafter referred to as an existing device), and the device C is an additional device.

  Here, a certain time period from the power synchronization signal detection point, for example, 2 ms, is defined as the additional apparatus transmission time period, and the transmission right acquisition time period of the existing apparatus is not set in this time period. The additional device C transmits the transmission data for the additional processing to the existing devices A and B during this time period. The data transmitted by the additional device C is a command in which the time required for transmission falls within this additional device transmission time zone.

Hereinafter, the process in the additional device C will be mainly described.
When the added device C detects the base point of the cycle from the voltage synchronization signal (step S1100: base point detection step), the device C starts a timer to measure the elapsed time from the base point of the cycle (step S1101: timer start step). ).

  Then, the setting value of the additional device transmission time zone is acquired from the management table of the own device C, and compared with the elapsed time of the timer, it is determined whether or not the elapsed time is within the range of the additional device transmission time zone ( Step S1102). In the sixth embodiment, since a certain time period from the power synchronization signal detection point is defined as the additional device transmission time period, when the power synchronization signal is detected in step S1100, the elapsed time of the timer is The additional device C is within the range of the additional device transmission time zone, and the additional device C determines whether or not the own device C is in a setting change confirmation waiting state (step S1103).

  Initially, since it is not in a setting change confirmation waiting state, a command for an addition request and a request to provide a transmission right acquisition time zone is issued to the existing devices A and B (step S1104), and this processing flow is performed again. Is started (START).

  In the sixth embodiment, the transmission right acquisition time zone request process includes steps S1100 to S1104. Note that the processing from step S1100 to step S1104 is made to fall within the additional device transmission time zone.

  Since the existing devices A and B execute the reception process in the additional device transmission time zone, they receive the command from the additional device C. When the existing devices A and B acquire the transmission right by the process described in the first embodiment, they return the additional permission response and the information on the set value of the transmission right acquisition information as a response to the command.

  The additional device C repeats the reception process in step S1106 until it is determined in step S1108 that the responses from the existing devices A and B are completely obtained. That is, since it is not yet in the setting change confirmation waiting state, the processes in steps S1100 to S1102 and steps S1106 to S1108 are repeated.

In addition, you may design so that acquisition of the response from the existing apparatuses A and B can be completed by one reception process (step S1106), without repeating this process flow.
If it is determined in step S1108 that the responses from the existing devices A and B have been completely obtained, the set value of the new transmission right acquisition time zone including the additional device is calculated (step S1109: calculation process), and the setting change confirmation wait state is entered. A transition is made (step S1110), and this processing flow is restarted (START).

  For example, in Western Japan (60 Hz region), the setting value of the transmission right acquisition time zone of the existing device A is 2.5 to 5 ms, and the setting value of the transmission right acquisition time zone of the device B is 5.5 to 7. In the case of 5 ms, the setting value of the transmission right acquisition time zone of the device A is 2.5 to 4 ms, the setting value of the transmission right acquisition time zone of the device B is 4.5 to 6 ms, and the transmission right acquisition of the device C is acquired. The set value of the time zone is assigned as 6.5 to 8 ms.

  After the transition to the setting change confirmation waiting state (step S1110), the determination result of step S1111 is “NO”, and when the base point of the next cycle of the power supply synchronization signal is detected, the determination result of step S1103 is “YES”. .

  However, the processing from the detection of the base point of the cycle of the power supply synchronization signal (step S1100) to the transition to the setting change confirmation wait state (step S1110) needs to be within one cycle of the power supply synchronization signal. Alternatively, after issuing a command for requesting provision of an additional request and a transmission right acquisition time zone to the existing devices A and B once (step S1104), steps are taken until responses from the existing devices A and B are obtained. It is necessary to devise such as not executing the processing of S1104. In addition, even if a predetermined time has elapsed (for example, the base point of the period of the power supply synchronization signal is detected five times), if there is still no response from each device, the additional request and the transmission right acquisition time zone A request for provision may be made.

Note that the processing may be suspended after the transition to the setting change confirmation wait state until the base point of the next cycle of the power supply synchronization signal is detected.
When a transition to the setting change confirmation wait state is made in step S1110 and the base point of the next cycle is detected, a request for changing the set value to the new transmission right acquisition time zone calculated in step S1109 is sent to the existing devices A and B Is issued (step S1105), and this processing flow is started again (START).

  Since the existing devices A and B execute the reception process in the additional device transmission time zone, they receive the command from the additional device C and change the setting value. When the existing devices A and B acquire the transmission right by the process described in the first embodiment, they return a response indicating that the setting value has been changed.

  The additional device C repeats the reception process in step S1106 until it is determined in step S1111 that acquisition of responses from the existing devices A and B is complete. That is, here, since the state is changed to the setting change confirmation waiting state, the processing of step S1100 to step S1102, step S1106, step S1107, and step S1111 is repeated.

In addition, you may design so that acquisition of the response from the existing apparatuses A and B can be completed by one reception process (step S1106), without repeating this process flow.
If it is determined in step S1111 that the response from the existing devices A and B is completely obtained, the setting value of the transmission right acquisition time zone of the own device C is updated (step S1112), and a transition is made to the addition completion state (step S1113). The flow of this additional process is terminated. Thereafter, normal data transmission / reception processing is performed in the same manner as the other existing devices A and B.

  However, the processing from the detection of the base point of the cycle of the second power supply synchronization signal (step S1100) to the transition to the addition completion state (step S1113) needs to be within one cycle of the power supply synchronization signal. Alternatively, after issuing a command for changing the set value to the new transmission right acquisition time zone to the existing devices A and B once (step S1105), the responses from the existing devices A and B are obtained. It is necessary to devise such as not to execute the process of step S1105 until. In addition, even if a predetermined time has elapsed (for example, the base point of the period of the power supply synchronization signal is detected five times), if there is still no response from each device, a new transmission right acquisition time zone is again entered. A setting value change request may be made.

As described above, according to the sixth embodiment, the device C can be added in two cycles of the power supply synchronization signal.
Here, the additional device transmission time zone is counted from the base point (power synchronization signal detection point) of the cycle, for example, within 2 ms. This is because it is necessary to set a location where synchronization can be achieved. According to the sixth embodiment, it is possible to dynamically add devices as shown in FIG.

The additional device transmission time zone can be arbitrarily changed by the device that has acquired the transmission right issuing a command for changing the additional device transmission time zone to another device.
Further, although the communication system described in the first embodiment has been described as an example, the communication system in the fourth embodiment can be similarly implemented. That is, an additional device transmission time zone is set for each cycle of the power supply synchronization signal, and the additional device transmits unique ID information to the existing device and information on the transition order of the transmittable device ID in the additional device transmission time zone. And a command for requesting a transition order setting of a new transmittable device ID including the ID of the additional device may be transmitted.

  In the description of the first to sixth embodiments, the power supply synchronization signal is used. However, in this case, it is necessary to cope with a case where a power failure occurs during communication. In order to realize the communication method in the first to sixth embodiments, any signal may be used as long as the signal is periodic. For this reason, any device transmits a periodic reference signal to all devices, or an external circuit. (IC or the like) transmits a signal having periodicity, so that the present invention can be applied to the first to sixth embodiments regardless of a power failure or the like, and even in a battery-driven state.

  In the first to sixth embodiments, the transmission right is acquired by transmitting the transmission right acquisition command. However, after the transmission right acquisition command is transmitted, the reception response from each device is obtained. There is also a method of determining that the transmission right of the own device has been established. In this case, it is possible to further maintain consistency with respect to acquisition of transmission rights with other devices.

  As described above, according to the first to sixth embodiments, since communication is performed based on the base point of the period of the power supply synchronization signal, the power supply synchronization signal in the house that is the same power supply line can be treated as constant. It is useful as a communication method and means in equipment. In addition, even in a single electric appliance using a commercial power source composed of a plurality of LSIs, it is useful as a communication method and means between LSIs by using a commercial power waveform (power synchronization signal) supplied from an outlet. Become.

In addition, if a circuit such as an IC / LSI that sends out periodic signals is provided, it will be useful as a communication method and means between LSIs in battery-powered electrical products.
In addition, data collision in half-duplex communication can be prevented by using the hardware function of an existing general LSI / microcomputer.

  The communication method according to the present invention can prevent a communication collision in a communication system using a half-duplex communication method. For example, communication between home network home appliances, or between LSIs in a single electric appliance composed of a plurality of LSIs. This is useful for communication and communication between LSIs in battery-powered electrical products.

The figure which shows an example of the communication system by the predetermined communication system in Embodiment 1-6 of this invention The figure which shows the flowchart of the data transmission / reception process of each apparatus in Embodiment 1 of this invention. Conceptual diagram of transmission right acquisition time zone of each device in Embodiment 1 of the present invention Conceptual diagram of transmission right acquisition time zone of each device in Embodiment 2 of the present invention The figure which shows the flowchart of the data transmission / reception process of each apparatus in Embodiment 3 of this invention. Conceptual diagram of transmission right acquisition time zone of each device in Embodiment 3 of the present invention The figure which shows the flowchart of the data transmission / reception process of each apparatus in Embodiment 4 of this invention. Conceptual diagram of transmission right acquisition time zone of each device in Embodiment 4 of the present invention The figure which shows the flowchart of the data transmission / reception process of apparatuses other than the master apparatus in Embodiment 5 of this invention. Conceptual diagram of transmission right acquisition time zone of each device in Embodiment 5 of the present invention The figure which shows the flowchart of the apparatus addition process of the additional apparatus in Embodiment 6 of this invention. Conceptual diagram of transmission right acquisition time zone and additional device transmission time zone of each device in Embodiment 6 of the present invention

Claims (17)

In a communication system in which communication is performed between a plurality of devices, each of the devices has a transmission right acquisition time zone in which a data transmission right can be acquired, which overlap each other for each period of a periodic signal. Is a communication method in which each of the devices transmits transmission data after acquiring the transmission right in the transmission right acquisition time zone of the device,
Each of the devices is
A base point detection step of detecting a base point of the period from the periodic signal input to each of the devices;
A timer starting step of starting a timer for measuring an elapsed time based on the detected base point;
A determination step of determining whether another device has already acquired the transmission right;
When another device has not acquired the transmission right, the transmission right acquisition time zone of the own device is compared with the elapsed time of the timer, and the elapsed time of the timer is the transmission right acquisition time zone of the own device. A transmission right acquisition step of acquiring a transmission right by issuing a transmission right acquisition command to another device,
A communication method comprising:   The communication method according to claim 1, further comprising a transmission right releasing step of releasing the transmission right when transmission of transmission data is completed.   The communication method according to claim 1, wherein the periodic signal is a power supply synchronization signal generated from a commercial power supply.   4. The communication method according to claim 1, wherein the device that has acquired the transmission right issues a command for changing the transmission right acquisition time zone set for each of the devices to other devices. By doing so, the transmission right acquisition time zone of each of the devices can be arbitrarily changed. In a communication system in which communication is performed between two devices, each of the devices has a transmission right acquisition time zone in which a data transmission right can be acquired, based on the base point of the periodic signal cycle. The communication method is set alternately, and each of the devices transmits transmission data after acquiring the transmission right in the transmission right acquisition time zone of the own device,
Each of the devices is
A determination step of determining whether the other device has already acquired the transmission right;
If the other device has not acquired the transmission right and is in the transmission right acquisition time zone of its own device, a transmission right for acquiring the transmission right by issuing a transmission right acquisition command to the other device Acquisition process,
A communication method comprising:   6. The communication method according to claim 5, wherein the periodic signal is a signal having one period longer than a time required for issuing the transmission right acquisition command.   7. The communication method according to claim 5, wherein two types of signals having different potential levels are generated alternately based on a base point of a period of the periodic signal as the transmission right acquisition time zone. The generation period is assigned to each of the devices, and when determining whether the transmission right acquisition time zone of the own device in the transmission right acquisition step, in any generation period of the two types of signals, A communication method characterized by determining whether or not there is.   8. The communication method according to claim 7, wherein the two types of signals are a signal having a potential level of H level and a signal having a potential level of L level.   9. The communication method according to claim 8, wherein each of the devices is capable of detecting a rising edge of the H-level signal and a falling edge of the L-level signal. When determining whether it is a transmission right acquisition time zone, it is determined whether the most recently detected edge is a rising edge of the H level signal or a falling edge of the L level signal. Communication method.   10. The communication method according to claim 5, further comprising a transmission right releasing step of releasing the transmission right when transmission of transmission data is completed.   The communication method according to claim 5, wherein the periodic signal is a power supply synchronization signal generated from a commercial power supply. In a communication system in which communication is performed between a plurality of devices, each of the devices is preset with an identifier of the own device, an initial value of the identifier of the transmittable device, and a transition order of the identifiers of the transmittable device. Communication in which each of the devices acquires the right to transmit data and transmits the transmission data when the identifier of the device matches the identifier of the device capable of transmission and transmission data exists in the device. A method,
Each of the devices is
A first determination step of determining whether another device has already acquired the transmission right;
A second determination step of determining whether or not a base point of a period of a periodic signal input to each of the devices is detected within a predetermined period when another device has not acquired the transmission right; When,
A third determination step of determining whether or not the identifier of the transmittable device and the identifier of the own device match when the base point is detected;
When the identifier of the transmittable device and the identifier of the own device match and there is no transmission data in the own device, the identifier of the next transmittable device according to the transition sequence of the identifier of the transmittable device is A setting step for setting each of the devices;
A transmission for acquiring a transmission right by issuing a transmission right acquisition command to another device when the identifier of the device capable of transmission matches the identifier of the own device and transmission data exists in the own device. Rights acquisition process,
Each of the devices has a transmission right acquisition time zone in which the transmission right acquisition time can be acquired by matching the identifier of the device capable of transmission with the identifier of the own device, and is one of the periodic signals. A communication method characterized by being assigned in units of periods.   13. The communication method according to claim 12, wherein one of the devices is determined in advance as a master device, and the master device identifies the transmittable device in response to a request from the own device or another device. A communication method characterized in that the transition order of identifiers of the transmittable devices can be arbitrarily changed by issuing a command for changing the transition order.   14. The communication method according to claim 12, further comprising a transmission right releasing step of releasing the transmission right when transmission of transmission data is completed.   15. The communication method according to claim 12, wherein the periodic signal is a power supply synchronization signal generated from a commercial power supply. The communication method according to any one of claims 1 to 4,
For each device of the communication system for which the transmission right acquisition time zone has already been set and each additional device to be added to the communication system, the additional device is a device for which the transmission right acquisition time zone has already been set. On the other hand, an additional device transmission time zone in which transmission data can be transmitted is preset in a range that does not overlap with the transmission right acquisition time zone for each cycle of the periodic signal,
The additional equipment is
When detecting the additional device transmission time zone, a transmission right acquisition time zone provision requesting step for requesting provision of the transmission right acquisition time zone to a device for which the transmission right acquisition time zone has already been set;
When obtaining the transmission right acquisition time zone from a device for which the transmission right acquisition time zone has already been set, a calculation step of calculating a new transmission right acquisition time zone including the own device;
When detecting the additional device transmission time zone, a new transmission right acquisition time zone setting requesting step for requesting the device for which the transmission right acquisition time zone has already been set to request setting of the new transmission right acquisition time zone;
A communication method comprising:   17. The communication method according to claim 16, wherein the device that has acquired the transmission right can arbitrarily change the additional device transmission time zone by issuing a command for changing the additional device transmission time zone to another device. Communication method.

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