JP2593842B2 - Communication method and apparatus for video information equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a video information device such as a VTR or a video disc player, a tuner, a timer, a video camera,
The present invention relates to a communication method between a peripheral device such as an editing machine and a computer.

[Conventional technology]

Mode information, control signals, and command signals are often communicated between a video information device and its peripheral devices, such as a VTR and a video camera or editing machine, for the purpose of synchronizing and operating these two devices. Is being done.

Heretofore, this type of communication has been performed in a state where there is no time relationship with the input or reproduced video signal. That is, for example, when the mode is changed, commands such as "reproduce next" and "stop next" are communicated.

[Problems to be solved by the invention]

If communication is performed only when necessary, such as when the mode changes as described above, if a communication error is made, the current mode will remain incorrect until the next mode change causes communication. Will be.

Further, since it is unknown when the transmission data arrives for the peripheral device, it must be always in an interruptible state and always in a communicable state, for example. This makes it difficult to create software.

Also, it is difficult for the video information device to create software because it is unknown when a command or the like from a peripheral device arrives.

Therefore, it is conceivable to perform communication periodically. However, if this cycle is arbitrary and is in an asynchronous state having no time relationship with the video signal, various inconveniences occur.

For example, recently, it has been practiced to record data such as a time code including a frame number and a field number by multiplexing the video signal with the video signal. If communication between periodic devices is performed at a period longer than the vertical period, for example, at some point the communication will overtake the frame number or field number of the time code, and the output of this time code will be missing. It will happen.

Furthermore, if the video signal is asynchronous, for example, in the case of the communication between the VTR and the editing machine, when there is a command "set the recording mode two fields from now"
The time "two fields from now" is not uniquely determined, making it very difficult to create software.

[Means for solving the problem]

In order to solve the above-mentioned problems, according to the present invention, between a video information device and its peripheral device, a single transmission line is used to periodically repeat a vertical synchronization signal with a certain phase relationship. A communication method for performing bidirectional communication repeatedly using a signal period, wherein the vertical signal period includes a communication and idle period and a wait period of a predetermined length following the period, and the interval of a normal vertical synchronization signal is the same as the above. The lengths of the communication and pause periods and the wait period are selected so as to be longer than the communication and pause periods and shorter than the sum of the communication and pause periods and the wait period. When the vertical synchronization signal is not within the wait period, the next communication is started at the end of the predetermined length wait period when the vertical synchronization signal is not within the wait period. Thus, communication is performed in a free-running cycle close to the cycle of the vertical signal period, and when the vertical synchronization signal enters the wait period again, communication is performed in synchronization with the vertical synchronization signal. An apparatus communication method and a communication apparatus using the method are provided.

[Action]

Communication is repeated at a period synchronized with the vertical synchronization signal. Therefore, even if a communication error is made once, it can be restored immediately. In addition, the relationship between the time code and the frame number or the like can be easily obtained, and when a predetermined command is issued in field units, the operation time of the command is uniquely determined.

〔Example〕

FIG. 2 shows an embodiment of the present invention, in which
R is an example in the case where the peripheral device is a video camera.

In this example, bidirectional serial data communication can be performed by one transmission line, and the VTR is the master side and the video camera is the slave side.

That is, in the figure, (10) is a VTR, and (20) is a video camera. The VTR (10) is equipped with a microcomputer (hereinafter referred to as "microcomputer") (110) and controls the communication and other controls (11), the video circuit and mechanical deck (12), and the VTR function keys (13). And V
It comprises a TR mode display section (14), a function key section (15) for remote control (hereinafter referred to as a remote controller) of the camera (20), and the like.

The video camera (20) is equipped with a microcomputer (210) and performs communication and other controls (21), a camera function key (22), and a VTR (10) remote control function key. (23) and, for example, a display section (24) adapted to be displayed in the viewfinder. A motor (25F) (2F) that rotates the focus ring and zoom ring of the imaging lens respectively
5Z) and an iris motor (25
I) is connected to the control unit (21) via the motor drive circuits (26F) (26Z) (26I).

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 section (13) of the VTR (10) has function keys such as recording, playback, pause, fast forward, rewind, and stop. When any of these keys is operated, the micro key of the control section (11) is operated. The computer (110) identifies it, displays it on the display unit (14), supplies necessary control signals to the video circuit and the mechanical deck unit (12), and sets the mode according to the key operated by the VTR. Is to be.

The VTR (10) remote control function key (23) of the video camera (20) also has function keys for recording, playback, pause, fast forward, rewind, stop, etc.
When any key is pressed, control data is transmitted from the camera (20) through the communication line (30) as described later.
The data is transmitted to the VTR (10) and is taken into the register of the microcomputer (110) of the control unit (11). The contents of the data and the function key (1) of the VTR (10) at that time are read.
The mode of the VTR (10) is determined from the state of the key input in 3), the mode is displayed on the display section (14), and the necessary control signals are supplied to the video circuit and the mechanical deck section (12). Mode. The mode of the VTR (10) is determined based on the data transmitted from the camera (20) and the state of the function key section (13) of the VTR (10) to prevent erroneous operations. In this case, the fast forward command is ignored and the recording state is continued.
This is done by storing in the microcomputer (110) which mode the VTR (10) should be in next for the combination of the mode of the remote control signal and the function key.

Also, from the VTR (10), signal data indicating that the mode has been entered is sent back to the camera (20), and the camera (20) receives the signal data and displays the VTR on the display unit (24) in the viewfinder. The mode display of (10) is displayed.

The function key section (15) for the remote controller of the camera (20) of the VTR (10) has keys for focus, iris, zoom, pan, tilt, and the like. For example, when the zoom key is operated, zooming data is transmitted as described later. From the VTR (10) to the camera (20) through the transmission line (30)
Is transmitted to the register of the microcomputer (210) of the control unit (21) of the camera (20), and the zooming data is transmitted through the motor drive circuit (26Z).
Z) to perform a zooming operation.

When the function key section (22) is operated on the camera (20), an operation corresponding to the key operation is performed on the camera (2).
In the step (0), the control is performed by a signal from the microcomputer (210) of the control unit (21). For example, operating a zoom key with the camera (20) is like performing a zooming operation.

Two-way communication through one transmission line (30) is performed as follows.

That is, the microcomputer (11) of the control unit (11) of the VTR (10)
0) and the microcomputer (210) of the video camera (20) are provided with 8-bit shift registers (111) and (211). These shift registers (111) and (211) are connected to the serial input terminal SI, respectively. And a serial output terminal SO and a clock terminal CK. The shift registers (111) and (211) are configured to write and read data in parallel data with the data bus of the microcomputer.

The capture of serial data into the shift registers (111) and (211) and the reading of serial data are controlled by the communication controllers (112) and (212), respectively. These communication controllers (112) and (21)
2) Signals for controlling ON / OFF of the input gate switches (113) and (213) and the output gate switches (114) and (214) of the shift registers (111) and (211), respectively.
G ₁ and G ₂ are generated, and the shift clock CLK (one cycle is, for example, 10) for the shift registers (111) and (211).
4 μsec).

The communication controller (112) on the VTR (10) side as the master device sends a communication start signal from the microcomputer (110).
Generate start bit based on CS. The communication controller (212) on the video camera (20) side of the slave device does not generate a start bit. These 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 output transistors (1
The collectors of 16) and (216) are resistors (117) and (217)
, The collector is connected to the transmission line (30), and the emitter is grounded. The serial data from the shift registers (111) and (211) are supplied to the bases of the output transistors (116) and (216) via the output switches (114) and (214).

In addition, the transmission line (30) is connected to the resistors (118) and (2
18) to the bases of the input transistors (115) and (215). And this transistor (115)
And the emitter of (215) is grounded and the collector is a resistor (1
The collector is grounded via 19) and (219), and this collector is connected to the serial input terminals of the shift registers (111) and (211) via the input switches (113) and (213).

In the above configuration, the VT as the master device
The two-way communication between R (10) and the video camera (20) as a slave device is, as shown in FIG.
It is repeated in a vertical cycle in synchronization with the vertical synchronization signal VD. That is, as shown in the figure, the VTR (10) is viewed from the VTR (10) side.
A transmission area P ₁ of the data DT ₁ from a video camera (2
A set of the reception area P ₂ of the data DT ₂ from 0) and the communication section as one block, a vertical synchronizing signal and which the pause interval
Together it is to repeat a vertical cycle in synchronization with VD, obtained this in VTR (10) of a start bit to 1 bit before each data DT ₁ and DT ₂ as the master device camera (20) Side, and data transmission and reception are performed based on the start bit. That is, start-stop synchronous data is transmitted.

Also, in this example, among the one block, transmission area P ₁ of the beginning transmission period of data from the VTR (10), the area P ₂ of the latter is the transmission period of the data from the video camera (20) have, but is adapted to generate at two start bits SB ₁ and SB ₂ is repeated constant period for one block from the VTR communication controller (10) (112). Also, 8-bit serial data is being transmitted in each of the transmission area P ₁ and P _2, constitute one word in this 8-bit data. In this case, since there are two communication areas in one block, two words of data are exchanged within one vertical cycle TF. Since the number of words and the number of bits in the communication section are fixed as described above, the length of the communication section is constant.

The communication for each block is performed as follows.

The microcomputer (110) of the master device generates a communication start signal CS (FIG. 3A), which is supplied to the communication controller (112). The communication start signal CS is normally "1", and falls to "0" when a communication start request is made. In this example, it falls to "0" twice for each vertical synchronization. The communication controller (112) receives the communication start request, for example, from the rising edge of the signal CS to the specified length 10
Start bit that will be “1” for a period of one bit of 4 μsec
SB ₁ (FIG. 3B) is obtained, which is the output transistor (1
The signal is supplied to the transmission line (30) to which the base is connected and the collector of which is connected as the signal of "0" whose polarity is inverted.

Moreover, the start bit SB ₁ followed by 8 clocks are pulses CLK of the clock period 104μsec from the communication controller (112) (Fig. 3 C) is obtained which is supplied to the clock terminal of the shift register (111) . The control signal G ₁ (FIG. 3D) of the output switch (114) is
The number of clock pulses CLK becomes “1”, and the output switch (114) is turned on. Microcomputer (11
0), the transmission data DT ₁ (third data) is stored in the shift register (111).
Since Figure F) is are set in advance, the transmission data DT ₁ of 8 bits from the shift register (111) by the eight clock pulses CLK is read, which is the output switch (1
14) and the transmission line (3
0). FIG. 3G shows the state of the signal on the transmission line (30) there. When transmission data DT ₁ of the 8 bits is fed out switch (114) is turned off, and therefore the transmission line (30) is pulled up to "1". The period of "1" continues for 2.5 to 5 bits. The period of 2.5 to 5 bits is an end bit. Normally, the end bit is about 2 bits, but in this case, since all of the processing is performed by the microcomputer software, the end bit is extended as described above, and the communication data is transferred to another RAM of the microcomputer.
The processing time for importing and storing the data is secured.

Thus transmission data transmitted from the master side in this area P ₁ is supplied to the base of the slave device of the video camera (20) side of the input transistor (215). Then, in the period of the start bit SB _1, the input transistor (215) is turned off, its collector output rises to "1". Then, the communication controller (21
This is detected in 2), and the control signal G ₁ ′ (FIG. 3I) of the input switch (213) becomes “1” and the eight cycles
A clock pulse CLK '(FIG. 3K) of 104 .mu.sec is obtained, and 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 from the VTR (10)
Is taken into the shift register (211). Then, while being stored is transferred to the RAM of the microcomputer (210) in its captured period data is an end bit, a video camera (20) data DT ₂ sent to VTR (10) from this shift register (211) Is set to

The communication start signal DA from the microcomputer (110) after a period of the end bit of the area P ₁ becomes "0" again, thereby the start bit SB ₂ (FIG. 3 of the area P ₂ from the communication controller (112) B) occurs, and the data on the transmission line (30) becomes "0" again for one bit period as shown in FIG. 3G. 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 then the output switch (2
Since the control signal G ₂ ′ of FIG. 14) (FIG. 3, J) becomes “1”,
With this output switch (214) is turned on, the eight clock pulses CLK 'is the signal G _2' is generated in the period of "1", which is supplied to the clock terminal of the shift register (211). Therefore, (see FIG. 3 H) read from the data DT ₂ is the shift register (211), it is supplied to the transmission line (30) through the output transistor (216).

Meanwhile, after outputting the start bit SB ₂ from VTR (10) side of the communication controller (112), input switch (113)
The control signal G ₂ (FIG. 3E) becomes “1”, the input switch (113) is turned on, and the eight clock pulses CLK (FIG. 3C) change the signal G ₂ to “1”. In a certain period.

Therefore the data transmitted from the video camera (20)
DT ₂ is supplied to a shift register (111) via an input transistor (115) and a switch (113) is incorporated into the shift register (111) by the clock pulse CLK.

Then, the are transferred to the RAM of the microcomputer (110) stores the period of the end bits of this area P _2.

Then, when the resting period after the communication path consisting of the area P ₁ and P _2, VTR (10) and the video camera (20)
In, processing based on the received data content is performed, and other tasks are also performed by time-division processing.

In the same way, transmission from the VTR (10) and camera (2
The communication section in which the transmission from 0) is set as one block is periodically repeated with the pause section narrowed. That is, this is intended communication start signal CS from the microcomputer (110) of the VTR (10) is a master device as a block point in the start bit SB ₁ and SB _2, which is adapted to periodically generated is there. As a result, the communication section and the pause section are reliably distinguished from each other, and the master side synchronizes the communication.

The above operations are executed according to the following programs of the microcomputers of the VTR (10) and the video camera (20).

That is, FIG. 4 is a flowchart of a program on the VTR (10) side, and steps (101) to (109) are sequentially repeated. Steps (105) to (107) are steps for determining the mode of the VTR (10) by giving priority to either the command from the camera (20) or the key operation on the VTR (10). This is for preventing malfunction.

Also, in the step (109) of generating the transmission content, the data corresponding to the key input operation on the VTR (10) side and the remote control signal from the camera (20) side appear on the VTR (10) side. In addition to generating data indicating the mode,
If there is no command or mode information to be sent to the camera (20), data containing "no operation required" is generated and transmitted.

FIG. 5 is a flowchart of a program on the video camera (10) side, and steps (201) to (208) are sequentially repeated. In this case, advance stored in the register to generate the transmission data in step (208), the data will be transmitted in step (204) waits until the start bit SB ₂ arrives.

The generation of start bits SB ₁ and SB ₂ in the communication controller (112), the generation of clock pulses,
The detection of the start bit and the generation of the clock pulse in the communication controller (212) may be respectively performed by microcomputer control, or may be performed by providing hardware separate from the microcomputer as shown in the example in the figure.

As described above, communication synchronized with the vertical synchronization signal VD is performed, but when a pseudo synchronization signal is mixed in the vertical synchronization signal or when the channel is changed by a TV tuner, the period of the vertical synchronization signal temporarily changes. Becomes disturbed. However, if an immediate response is made, there is a possibility that the communication contents may be interrupted on the way or may hinder other tasks other than the usual.

Therefore, the following method is used 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 synchronizing signal VD (FIG. 6A) is supplied to the microcomputer (110), no work is performed when a time S satisfying TF> S, for example, S = 15 msec, elapses from the time of the leading edge of the vertical synchronizing signal VD. It is in the state of weight (see FIG. 6B). That is, the communication section starts from the time point of the vertical synchronization signal VD, and then becomes a pause section until S elapses from the leading edge of the vertical synchronization signal VD (regular cycle is 16.7 msec) in which other work other than communication is performed. Work is finished
It becomes a state of weight.

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

Next, as shown in FIG. 6A, when the period of the vertical synchronizing signal VD is disturbed due to channel switching or the like, as shown in the corresponding part of FIG. The communication is released and communication is performed. Of course, if the vertical synchronization signal VD arrives before the lapse of 3 msec, the wait is canceled there. That is, 3msec
It will be released without waiting. That is, it follows the disturbance of the vertical synchronization signal within ± ΔS / 2. However, if a disturbance of ± ΔS / 2 or more occurs, communication is continued for a while without synchronization with the vertical synchronization signal VD at the self-running cycle of S + ΔS determined by the microcomputer (110), and thereafter the vertical synchronization signal VD is again
In the wait period of S, communication is performed in synchronization with the vertical synchronization signal VD.

That is, when the vertical synchronization signal VD is disturbed, the vertical period TF
, A window having a width of ± ΔS / 2 is provided. Synchronization disturbance is detected by the absence of the vertical synchronization signal VD in this window, and communication is performed in a self-running cycle of S + ΔS until the window enters the window. become. Incidentally, whether Recovery in how long so as to synchronize with the vertical synchronizing signal VD determined by the window width [Delta] S, the spacing of the vertical synchronizing signal when large changes as shown in FIG. 6 and X _1, vertical sync Assuming that the periodic error of the signal VD itself is ± ΔT, After the period, the vertical synchronizing signal VD enters the window again and locks.

Thus, communication can be performed in synchronization with the vertical synchronizing signal VD by configuring the PLL circuit with software by the microcomputer.

Therefore, even if the vertical synchronizing signal is suddenly disturbed or the synchronizing signal becomes weak and synchronization is lost, the PLL by the microcomputer software synchronizes itself.
Communication will not be disturbed and will soon follow again.

In the case of the above example, the end bit is longer than usual and the processing time for sending and receiving data is made, so the process of reading and writing serial data by software becomes easy, and the hardware There is an advantage that no extra latch circuit is required.

Also, it has good compatibility with RS-232C as an interface standard often used for this kind of communication. That is, the communication method according to the above example can be read only by voltage conversion 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 leak once or a communication error is made, the correct contents can be immediately restored.

In addition, since all communication and other tasks can be performed by a one-chip microcomputer without using an expensive interface, bidirectional digital data communication can be realized with a cheap consumer LSI and a single transmission line.

Since the communication is synchronized on the master device side, even if a plurality of jobs A, B, C, and D must be processed in a time-sharing manner in addition to communication, one job is interrupted. No more stopping.

That is, when communication is not synchronized and an expensive interface is not used, communication is performed in the middle of one job as shown in FIG. 7A, and other jobs may not be processed. However, in this example, communication is synchronized on the master side and work is performed in a pause section of a fixed length, so that the management of the time division multiplexing processing becomes easy as shown in FIG. 7B. Therefore, there is an advantage that processing can be performed by an inexpensive microcomputer.

In the above example, there is one slave unit with respect to the master unit, and there are two communication areas in the communication section. However, the number of communication areas is three or more and, for example, the reception area is viewed from the master side. A total of four areas may be provided, two transmission areas each. In this case, the communication start signal from the microcomputer (110) occurs four times in the communication section, and is repeated.

Also, not one slave device but two or more slave devices
It can also be connected to three transmission lines. In that 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, or the communication area may be smaller than the number of slave devices. A vacant area may be used.

In the above example, communication is started in synchronization with the vertical synchronizing signal VD itself for the sake of simplicity. However, a signal synchronizing with the vertical synchronizing signal, for example, a signal PG indicating the rotational phase of the rotary head or two rotary heads The communication may be started in synchronization with the switching signal.

〔The invention's effect〕

As described above, since communication is performed periodically according to the present invention, even if there is one communication error, the correct state is restored by sending correct data by the next communication. Moreover, since the present invention performs communication synchronized with a signal synchronized with a vertical synchronization signal, a signal corresponding to a frame or a field of a video signal such as a frame number can be sent out as communication data.

Further, since the timing of communication can be predicted, hardware design of peripherals and the main body becomes easy.

Furthermore, since the communication is synchronized with the vertical cycle, it is easy to determine whether noise has jumped into an image due to the communication, and there is an effect that the debug (Debug) period can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the outline of the present invention, FIG. 2 is a system diagram of one embodiment of the present invention, FIGS. 3 to 6 are diagrams for explaining the embodiment, and FIG. It is a figure for explaining an effect of an example. (10) is a VTR as a video information device, (20) is a video camera as a peripheral device, (30) is one transmission line, P ₁ and P ₂
Is a communication area.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Mitsuru Ishihara 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Masahiko Machida 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (56) References JP-A-49-108927 (JP, A) JP-A-51-66717 (JP, A)

Claims (2)

(57) [Claims] 1. A two-way communication between a video information device and its peripheral device using a single transmission line using a vertical signal period that is periodically repeated with a constant phase relationship with a vertical synchronization signal. In the communication method to be performed, the vertical signal period includes a communication and pause interval and a wait period of a predetermined length following the interval, a regular vertical synchronization signal interval is longer than the communication and pause interval, and the communication and pause interval And the length of the wait period is selected so as to be shorter than the sum of the above and the wait period. When the vertical synchronization signal is within the wait period, communication is performed in synchronization with the vertical synchronization signal. When the vertical synchronization signal is not within the wait period, the next communication is started at the end of the predetermined length wait period, whereby the vertical signal period Communicates with self-propelled period close to the period, when the vertical synchronizing signal enters again into the wait period is to perform the communication in synchronization with the vertical synchronization signal, a method of communicating video information devices. 2. A communication device for performing two-way communication between a video information device and its peripheral device by using a single transmission line, wherein the vertical synchronization signal is periodically repeated with a certain phase relationship with a vertical synchronization signal. Communication means for repeatedly performing communication using a signal period, wherein the vertical signal period includes a communication and pause period and a wait period of a predetermined length following the period, and a normal vertical synchronization signal interval is longer than the communication and pause period. A wait period generating means for generating a wait period that is shorter than the sum of the communication and pause periods and the wait period, and detecting whether the vertical synchronization signal is within the wait period. Means for performing communication in synchronization with the vertical synchronization signal when the vertical synchronization signal is within the wait period, and when the vertical synchronization signal is not within the wait period. When the wait period of the predetermined length ends, the next communication is started to perform communication in a free-running cycle close to the cycle of the vertical signal period, and the vertical synchronization signal enters the wait period again. A communication device for a video information device, wherein communication is performed in synchronization with the vertical synchronization signal.