KR950000831B1 - Communication method and apparatus - Google Patents

Abstract

No content.

Description

Video information device communication method and communication device

1 is a view for explaining the outline of the present invention.

2 is a schematic diagram of one embodiment of the present invention.

3 to 6 are diagrams for explanation thereof.

7 is a diagram for explaining the effect of this embodiment.

* Explanation of symbols for main parts of the drawings

10: VTR as a video information device 20: Video camera as a peripheral device

30: 1 transmission line R ₁ , R ₂ : communication area

The present invention relates to a communication method and a communication device between, for example, a video information device such as a VTR or a video disc player, and peripheral devices such as a tuner, a timer, a video camera, an editor, and a computer.

Communication between mutual mode signals, control signals, and command signals for the purpose of synchronously operating these two devices between a video information device and its peripheral devices, such as a VTR and a video camera or editor. Is often done.

Conventionally, this kind of communication has been performed in a state not related to an input or playback video signal. That is, for example, when the mode was changed, commands such as "Next play" and "Next stop" were made to communicate.

In the case where communication is performed only when necessary, such as when the mode is changed as described above, if a communication miss is committed, the current mode remains wrong until the next communication for mode change is performed.

In the peripheral device, it is not possible to know when the transmission data arrives. For example, the peripheral device must always be in the interruptible state and always in the communicable state. Therefore, it is difficult to write software.

Moreover, even in a video information apparatus, it is difficult to write software because it is impossible to know when a command from a peripheral device or the like arrives.

Thus, periodical communication is considered. However, if this period is arbitrary and is an asynchronous state having no time relationship with the video signal, various problems arise.

For example, in recent years, recording of data such as a time code including a frame number, a field number, etc. by multiplexing on a video signal has been performed, but in such a case, when communicating these time codes, the VTR and the peripheral device are used. If the communication is performed in a period longer than the vertical period, for example, the communication side may overtake the frame number or field number of the time code, and thus a defect occurs in the output of this time code.

In addition, if the video signal is asynchronous, for example, in the case of communication between the VTR and the editor, when there is a command to "record mode at the point of time two fields from now", "after two fields from now" Since the time to do it is not uniquely determined, writing software becomes very difficult.

The present invention relates to a communication method and a communication device between an image information device and its peripheral device, and to perform communication repeatedly at a period synchronized with a vertical period signal having a constant phase relationship with the vertical synchronization signal.

The communication method of a video information device of the present invention is a bidirectional communication method by means of one transmission line between a video information device and its peripheral device, the signal having a vertical period in constant phase relation with the vertical synchronization signal. When the communication of the vertical period is in a window of a predetermined width generated after the period of time smaller than the vertical period and the next communication is started according to the vertical synchronization signal, the communication of the vertical period is repeated. The communication is performed in synchronization with the signal of the vertical period, and when it is not in the window, the next communication is started at the time when the window of the predetermined width ends, so that the communication is performed in a self-period period approximately equal to the vertical period. do.

In addition, the communication apparatus of the video information apparatus of the present invention is a bidirectional communication apparatus by means of one transmission line between the video information apparatus and its peripheral apparatuses, and is synchronized with the vertical synchronous signal and a signal having a vertical period in constant phase relation. Communication means for repeatedly performing communication at one cycle, window generating means for generating a window having a predetermined width from the time after a period less than the vertical period elapses until the next communication starts according to the vertical synchronizing signal, and the vertical period Detection means for detecting whether or not the signal is within the window. When the signal of the vertical period is within a window of a predetermined width, the detection means performs communication in synchronization with the signal of the vertical period. When not in use, it is characterized in that communication is carried out at an independent period approximately equal to the vertical period.

According to the present invention as described above, communication is repeated at a period synchronized with the vertical synchronization signal. Therefore, it is possible to return immediately after one communication miss. In addition, the relationship between the time code frame number and the like becomes easy, and when there is a predetermined command in the field unit, the time of operation by the command is uniquely determined.

Next, embodiments of the present invention will be described in detail with reference to the drawings.

2 is an example of the present invention, where the image information is a VTR and the peripheral device is a video camera.

In this example, serial data communication can be carried out bidirectionally by one transmission line, with the VTR being the master side and the video camera being the slave side.

That is, in FIG. 2, reference numeral 10 denotes a VTR, and 20 denotes a video camera. The VTR 10 includes a control unit 11 mounted with a microcomputer 110 to control communications and the like, a video circuit and mechanism deck unit 12, a function key unit 13 of the VTR 10, and a VTR mode. And a display unit 14 and a function key unit 15 for a remote control (hereinafter referred to as a remote controller) of the camera 20.

In addition, the video camera 20 is equipped with a microcomputer 210 to control a communication and other control unit 21, a function key unit 22 of the camera, and a function key unit 23 for a remote control of the VTR 10. And a display unit 24 which can be displayed, for example, in the finder. The motor 25F, 25Z, which rotates the focus ring and the zoom ring of the imaging lens, and the iris motor 25I, which controls the opening and closing degree of the aperture, respectively, are provided via the motor drive circuits 26F, 26Z, 26I. It is connected to the control unit 21.

Reference numeral 30 denotes one data transmission line for transmitting a control signal between the VTR 10 and the video camera 20.

The function key unit 13 of the VTR 10 has function keys such as recording, playback, pause, feeding, rewinding, and stop, and when any one of these keys is operated, the microcomputer 110 of the control unit 11 is operated. Identifies it, displays it on the display unit 14, and supplies the necessary control signal to the video circuit and the mechanism deck unit 12, and the VTR enters the mode according to the operated key.

The function key 23 for the remote control of the VTR 10 on the side of the video camera 20 also has function keys such as recording, playback, pause, feeding, rewinding, and stop. As described above, control data is transmitted from the camera 20 side to the VTR 10 via the communication line transmission line 30, which is taken into the register of the microcomputer 110 of the control unit 11, and the contents of the data and At this time, the mode of the VTR 10 is determined from the key input state of the function key unit 13 of the VTR 10, and the mode display is performed on the display unit 14, and the video circuit and the mechanism deck unit 12 A control signal necessary for N) is supplied to bring the mode into the mode. Determining the mode of the VTR 10 from the transmission data from the camera 20 and the state of the function key section 13 of the VTR 10 is to prevent misoperation, for example, a mode called feeding during camera recording. Is normally not used. At this time, the feeding instruction is ignored and recording continues. This is done by having the microcomputer 110 store which mode the VTR 10 should be made next for the combination of the mode of the remote control signal and the function key.

In addition, the VTR 10 sends signal data indicating that the mode has been entered to the camera 20 side, and receives it from the camera 20 side, and displays the mode of the VTR 10 on the display unit 24 in the finder. Is performed.

The function key 15 for the remote control of the camera 20 of the VTR 10 has keys such as focus, iris, zoom, pan, and tilde. For example, when the zoom key is operated, zooming data will be described later. To the camera 20 from the VTR 10 via the transmission line 30, and inserted into the register of the microcomputer 210 of the control unit 21 of the camera 20, and the zooming data motor drive circuit ( The zoom motor 25Z is supplied to the zoom motor 25Z to perform zooming.

When the function key unit 22 is operated in the camera 20, the operation according to the key operation is performed by the signal from the microcomputer 210 of the control unit 21 in the camera 20. For example, when the zoom key is operated in the camera 20, the zooming operation is performed.

Bidirectional communication via one transmission line 30 is performed as follows.

That is, 8-bit shift registers 111 and 211 are provided in the microcomputer 110 of the control unit 11 of the VTR 10 and the microcomputer 210 of the video camera 20. Reference numerals 111 and 211 each have a serial input terminal SI, a serial output terminal SO, and a clock terminal CK. The shift registers 111 and 211 are configured to read and write in the state of parallel data between the data bus of the microcomputer.

In addition, the serial data into and out of the shift registers 111 and 211 are controlled by the communication controllers 112 and 211, respectively. These communication controllers 112 and 212 control signals for turning on and off the input gate switches 113 and 213 and the output gate switches 114 and 214 of the shift registers 111 and 211, respectively. While generating G ₁ · G ₂ , the shift clock CLK (one cycle is 104 μsec, for example) for the shift registers 111 and 211 is generated.

The communication controller 112 on the VTR 10 side as a master device generates a start bit in accordance with the communication start signal CS from the microcomputer 110. The start controller does not generate the communication controller 212 on the video camera 20 side of the slave device. The communication controllers 112 and 212 can also be realized by a microcomputer.

115 and 215 are input transistors, 116 and 216 are output transistors, and the collectors of the output transistors 116 and 216 are connected to the power supply terminals via resistors 117 and 217. At the same time, this collector is connected to the transmission line 30, and the emitter is grounded. The serial data from the shift registers 111 and 211 is supplied to the bases of the output transistors 116 and 216 through the output switches 114 and 214.

In addition, the transmission line 30 is supplied to the bases of the input transistors 115 and 215 through the resistors 118 and 218, respectively. The emitters of the transistors 115 and 215 are grounded, and the collector is connected to the power supply terminal via resistors 119 and 219 while the collector is shifted through the input switches 113 and 213. It is connected to the serial input terminals of the transistors 111 and 211.

In the above configuration, bidirectional communication between the VTR 10 as a master device and the video camera 20 as a slave device is repeated in a vertical period in synchronization with the vertical synchronization signal VD in this example, as shown in FIG. do. That is, as shown in Fig. 1, the _pair of the transmission area P ₁ of the data DT ₁ from the VTR 10 and the reception area P ₂ of the data DT ₂ from the video camera 20 as seen from the VTR 10 side ( I) as one block, which is used as a communication section, and this section and the idle section are repeated in a vertical period in synchronization with the vertical synchronization signal VD, and a start bit is provided for one bit before each data DT ₁ and DT ₂ ; Is obtained by the VTR 10 as a master device, and is transmitted to the camera 20 side, and data transmission and reception are performed in accordance with this start bit. That is, the coarse synchronization type data transmission is performed.

In this example, the first transmission area P ₁ of one block is between the transmitters of the data from the VTR 10, and the subsequent area P ₂ is between the transmitters of the data from the video camera 20. From the communication controller 112, two start bits SB ₁ and SB ₂ for one block are repeatedly generated at regular intervals. The transmission area and is serial data of 8 bits to be transmitted in each of P ₁ and P _2, thereby constituting the first word of data from this 8-bit. In this case, since there are two communication areas in one block, two words of data are transmitted and received within one vertical period TF. In this way, since the number of words and bits in the communication section are fixed, the length of the communication section is constant.

And communication per block is performed as follows.

The communication start signal CS (FIG. 3a) is generated from the microcomputer 110 of the master device, and this is supplied to the communication controller 112. This communication start signal CS is calculated as "1", and drops to "0" when the communication start request is made. In this example, it descends to "0" twice per vertical period. In the communication controller 112, when this communication start request is made, for example, a start bit SB ₁ (Fig. 3B) which becomes a period " 1 " for a prescribed length of 104 mu sec from the time when the signal CS rises is obtained. This is supplied to the base of the output transistor 116, and is supplied as a signal of " 0 " reversed in polarity to the transmission line 30 to which the collector is connected.

Subsequently to the start bit SB ₁ , eight communication pulses CLK (third c) having a clock period of 104 sec are obtained from the communication controller 112, which is supplied to the clock terminal of the shift register 111. The control signal G ₁ (third degree d) of the output switch 114 becomes the period " 1 " of these eight clock pulses CLK, so that the output switch 114 is turned on. In the microcomputer 110, the shift is performed. Since the transmission data DT ₁ (third figure) is set in advance in the register 111, the 8-bit transmission data DT ₁ is read out from the shift register 111 by the eight clock pulses CLK. 114 and the output transistor 116 are supplied to the transmission line 30. 3G shows the state of the signal on this transmission line 30. When this 8-bit transmission data DT ₁ is sent out, the switch 114 is turned off, thereby causing the transmission line 30 to rise to "1". The period of " 1 " continues for 2.5 to 5 bits. This 2.5 to 5 bit period is an end bit. Usually, the end bit is about 2 bits, but in this example, since all of the software is processed by the microcomputer, the end bit is extended in this way than usual, so that the communication data can be inserted into or stored in another RAM of the microcomputer. The processing time is secured.

In this way, the transmission data transmitted from the master side in the area P ₁ is supplied to the base of the input transistor 215 on the video camera 20 side of the slave device. In the period of the start bit SB ₁ , this input transistor 215 is turned off, and its collector output rises to " 1 ". Then, this is detected by the communication controller 212, so that the control signal G ₁ '(third figure i) of the input switch 213 becomes "1" and at the same time, clock pulse CLK' with eight cycles of 104 mu sec. k) is obtained, the switch 213 is turned on, and the clock pulse CLK 'is supplied to the clock terminal of the shift register 211. Therefore, the transmission data DT ₁ is taken into this shift register 211 from the VTR 10. The captured data is transferred to the RAM of the microcomputer 210 in the end bit period and stored therein, and data DT ₂ sent from the video camera 20 to the VTR 10 is transferred to the shift register 211. Is set.

Then, the area after the period of the end bits of P ₁ a communication start signal DA from the microcomputer 110, and back to "0", whereby the start bit SB ₂ (a third of the area P ₂ in the communication controller 112 also b ) Is generated, and as shown in FIG. 3G, the data on the transmission line 30 is again in the state of one bit period "0". Therefore, the input transistor 215 of the video camera 20 is turned off, and its collector output becomes "1". The communication controller 212 detects this, and this time, the control signal G ₂ ′ (third figure j) of the output switch 214 becomes “1”, so that this output switch 214 is turned on and eight The clock pulse CLK 'is generated in the period of "1" of this signal G ₂ ', and this is supplied to the clock terminal of the shift register 211. Therefore, the data DT ₂ is read out from this shift register 211 (see FIG. 3H) and supplied to the transmission line 30 through the output transistor 216.

On the other hand, after the start bit SB ₂ is output from the communication controller 112 on the VTR 10 side, the control signal G ₂ (FIG. 3E) of the input switch 113 becomes "1". 113 at the same time is turned on, the eight clock pulse CLK (Fig. 3 c) is obtained in a period in which the signal G ₂ '1'.

Therefore, the data DT ₂ transmitted from the video camera 20 is supplied to the shift register 111 through the input transistor 115 and the switch 113, and is taken in to the shift register 111 by the clock pulse CLK.

Then, it is transferred to and stored in the RAM of the microcomputer 110 in the period of the end bit of this area P ₂ .

Then, in the drawing, the VTR 10 and the video camera 20 in the pause section after the communication section composed of the areas P ₁ and P ₂ , processing according to the received data content is performed and other work is also time-divided. Is done.

Next, in the same manner, the communication section in which transmission from the VTR 10 and transmission from the camera 20 is made into one block is periodically repeated with the pause section in between. In other words, this means that the communication start signal CS from the microcomputer 110 of the VTR 10, which is the master device, is generated periodically, with the time points of the start bits SB ₁ and SB ₂ as one block. As a result, the communication section and the idle section are clearly distinguished, and the master is synchronously communicating.

The above operation is executed in accordance with the following program of each microcomputer of the VTR 10 and the video camera.

That is, FIG. 4 is a flowchart of the program on the VTR 10 side, and steps 101 to 109 are repeated sequentially. Here, steps 105 to 107 are steps for determining the mode of the VTR 10 in preference to giving the instruction from the camera 20 described above and key operation in the VTR 10, and malfunctioning. Is for the prevention of.

In step 109 of generating the transmission contents, the mode that is present on the VTR 10 side by the data corresponding to the key input operation on the VTR 10 side and the remote control signal from the camera 20 side is indicated. In addition to the data being generated, when there is no command or mode information to be sent to the camera 20 side, data having a content of "no operation required" is generated and transmitted.

5 is a flowchart of a program on the video camera 10 side, and steps 201 to 208 are sequentially repeated. In this case, in step 208, transmission data is generated and stored in a register, and the data is transmitted in step 204 after waiting for the start bit SB ₂ to arrive.

The generation of the start bits SB ₁ and SB _{2 in} the communication controller 112, the generation of the clock pulses, the detection of the start bits in the communication controller 212, and the generation of the clock pulses are performed by microcomputer control, respectively. As shown in the drawing, hardware may be provided separately from the microcomputer.

As described above, the synchronous communication is performed in synchronization with the vertical synchronous signal VD. However, when the pseudo synchronous signal is mixed with the vertical synchronous signal or the channel is switched by a TV tuner, the period of the vertical synchronous signal is temporarily confused. It becomes However, responding immediately to this may cause the communication to be interrupted or cause problems other than the communication.

Therefore, the following is to deal with the disturbance of the vertical synchronization signal.

The following processing is performed by software by the microcomputer 110 of the VTR 10 of the communication master device.

That is, when the vertical synchronous signal VD (FIG. 6A) is supplied to the microcomputer 110, when the time S at which TF> S becomes, for example, S = 15 msec has elapsed from the point in front of the vertical synchronous signal VD, In the standby state without work (see Fig. 6b), i.e., from the time point of the vertical synchronization signal VD to the communication section, and then to the rest period, other work other than communication is performed, but the vertical synchronization signal VD (The regular cycle is 16.7 msec.) And the work ends until T elapses, and the standby state is reached.

When the vertical synchronizing signal VD is not confused, the next vertical synchronizing signal VD arrives at a period of time TF, the atmosphere is released at that point, and communication is started (see FIG. 6B).

Next, when the period of the vertical synchronization signal VD is disrupted due to channel switching or the like as shown in FIG. 6A, the air is released when the period [Delta] S, for example, 3 msec. Communication takes place. Of course, if the vertical synchronization signal VD arrives before 3 msec has elapsed, the atmosphere is released there. In other words, it is released without waiting for 3 msec. In other words, chaos of the vertical synchronization signal of ± DELTA S / 2 is followed. However, if confusion of ± DELTA S / 2 occurs, the communication is continued for a period of time S + DELTA S determined by the microcomputer 110 without being synchronized with the vertical synchronization signal VD for a while, and then vertical synchronization is again performed. When the signal VD enters the waiting period of DELTA S, communication is performed in synchronization with the vertical synchronization signal VD.

주기 후에 수지동기신호 VD가 다시 윈도내에 들어가서 로크하게 된다.That is, when the vertical synchronizing signal VD is confused, a window having a width of ± DELTA S / 2 is formed with respect to the vertical period TF, and since the vertical synchronizing signal VD does not enter in this window, synchronous confusion is detected and it enters the window. Communication takes place at an independent cycle of S + ΔS. Therefore, the interval of the vertical synchronization signals of the time do some time to return to synchronization with the vertical synchronizing signal VD of a is determined by the width △ S of the window, significantly as shown in Figure 6 byeonhaeteul to X _1, and the vertical If the period error of the synchronization signal VD itself is ± DELTA T,

After the period, the resin synchronization signal VD enters the window again and locks.

In this way, by configuring the PLL circuit with software by the microcomputer, it is possible to communicate in synchronization with the vertical synchronization signal VD.

Therefore, even if the vertical synchronization signal suddenly becomes disturbed or the synchronization signal becomes weak and cannot be synchronized, the synchronization is performed by the PLL by the software of the microcomputer itself, so that communication is not confused and immediately follows.

In the above example, since the end bit is longer than usual, the processing time of the transmission / reception data is made longer, which makes it easier to process serial data by reading and writing data in software, and also requires an extra latch circuit in terms of hardware. There is an advantage not to.

In addition, the interface standard which is well used for this kind of communication has good compatibility with RS-232C. That is, the communication method according to the above example can be read only by the voltage change by using the RS-232C communication channel.

In addition, since communication is not performed only when necessary, but is performed periodically, even if there is a communication loss once or a communication miss is committed, the contents can be immediately returned.

In addition, since communication and other work can be performed by a single-chip microcomputer without using expensive interfaces, bidirectional digital data communication can be realized by a low-cost consumer LSI and one transmission line.

Since the synchronization of the communication is taken from the master device side, even when a plurality of jobs A, B, C, and D must be processed by time division other than communication, one job is not stopped midway.

In other words, when the communication is not synchronized and the expensive interface is not used, as shown in FIG. 7A, communication is performed in the middle of one job and other tasks cannot be processed. In the example, since the master is synchronized with the communication and works in a rest period of a certain length, management of time division multiplexing is facilitated as shown in FIG. Therefore, there is an advantage that it can be processed by an inexpensive microcomputer.

In the above example, one slave device is used for the master device and there are two communication areas in the communication section. However, if the communication area is three or more, for example, two receiving areas and two sending areas are viewed from the master side. Four areas may be provided in total. In this case, the communication start signal from the microcomputer 110 is generated four times in the communication section, and it is repeated.

In addition, two or more slave devices may be connected to the same transmission line. In this case, the communication area in the communication section may be provided twice as many as the number of slave devices, and each area may be allocated to each slave device for communication, and the communication area may be less than the number of slave devices, and the area may be empty. May be used.

Incidentally, in the above example, communication is started in synchronization with the vertical synchronous signal VD for simplicity of explanation. The communication may be started in synchronization with the signal.

As described above, according to the present invention, communication is performed periodically, and even if there is a communication miss once, the correct data is sent by the next communication to return to the correct state. In addition, since the present invention performs communication in synchronization with a signal synchronized with the vertical synchronization signal, signals corresponding to frames and fields of video signals such as frame numbers can be sent as communication data.

In addition, since the timing of communication can be predicted, the hardware design of the periphery and the main body is facilitated.

In addition, since the communication is synchronized in the vertical period, it is possible to easily determine that the noise to the image by the communication is interrupted and to reduce the debug period.

Claims (2)

In the two-way communication method between a video information device and its peripheral device, the communication is repeatedly performed at a period synchronized with a vertical synchronization signal and a vertical period signal having a constant phase relationship. When the signal of the vertical period is in a window of a predetermined width generated after a period of time smaller than the vertical period has elapsed from the vertical period according to the vertical synchronization signal, communication is performed in synchronization with the signal of the vertical period, A communication method of a video information apparatus, wherein when not in a window, communication is performed at an independent period approximately equal to a vertical period by starting the next communication when the window of the predetermined width ends. A two-way communication device between a video information device and a peripheral device by one transmission line, comprising: communication means for repeatedly performing communication at a period in synchronization with a vertical synchronization signal and a signal of a vertical period having a constant phase relation, and the vertical unit; A window generating means for generating a window having a predetermined width after a period of time smaller than the vertical period from the time when the period is smaller than the vertical period, and detecting whether the signal of the vertical period is within the window; Means for performing communication in synchronism with the signal of the vertical period when the signal of the vertical period is within a window of a predetermined width, and by means of this detection means for communication in an independent period approximately equal to the vertical period when not in the window. Communication apparatus of the video information device, characterized in that the.

Images