JP3852340B2 - Optical transmission apparatus and optical data link control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical transmission apparatus configured to include a single central processing unit and a plurality of optical data links, and an optical data link control method executed in the optical transmission apparatus.
[0002]
[Prior art]
The optical transmission apparatus incorporates devices such as an optical data link and a central processing unit (CPU), and these devices include a serial clock line (SCL) for transmitting a clock signal and a serial data line for transmitting a data signal. They are connected to each other by a communication bus composed of two (SDA) bus lines. At this time, slave addresses are assigned to the optical data links, and a plurality of optical data links may be connected to the same communication bus, and the CPU performs setting and status monitoring of each optical data link using the communication bus. .
[0003]
In such an optical transmission apparatus, when information is written from the CPU to the optical data link, the clock signal and the header portion of the data signal are first output from the CPU, and the optical data link with the matching slave address follows from the CPU. An output data signal and a clock signal corresponding to the data signal are captured.
[0004]
Also, in this optical transmission apparatus, when the CPU reads information from the optical data link, the clock signal and the header of the data signal are first output from the CPU, and the optical data link whose slave address matches is the clock from the CPU. A data signal is output according to the signal.
[0005]
As described above, the optical data link supports reading / writing of the data signal only when the slave address stored in the header portion of the data signal matches the own slave address.
[0006]
For this reason, when a plurality of optical data links are connected to the same communication bus, the slave addresses of the optical data links must all be different. As a method for realizing the above, (1) a built-in nonvolatile memory of the optical data link is used. (2) A method of storing slave addresses on a board on which an optical data link is mounted by providing external hardware setting pins.
[0007]
[Problems to be solved by the invention]
However, in the method (1), it is necessary to determine the slave address for each individual at the time of factory manufacture or when the user implements, and the management work becomes complicated on both the manufacturer side and the user side. In the method (2), an optical data link provided with external hardware setting pins may be used. However, there are cases where the number of pins is small and a new pin cannot be provided as in a so-called SFP link.
[0008]
For this reason, there is a case where only the same slave address can be assigned to the optical data link. In such a case, all the optical data links react in the same way to read / write signals from the CPU, so that a plurality of There is a disadvantage that communication from the CPU cannot be performed by connecting the optical data link to the same communication bus.
[0009]
The present invention has been made to solve the above-described problems, and an optical transmission apparatus capable of performing communication from a CPU to a target optical data link in a configuration in which a plurality of optical data links are connected to the same communication bus. An object of the present invention is to provide an optical data link control method.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, an optical transmission apparatus according to the present invention includes a single central processing unit that outputs a data signal in which a slave address of a data transmission destination device is stored as destination information, and a data bus. A plurality of optical data links that are connected to the central processing unit and assigned a common slave address, and are connected to each optical data link and the central processing unit via a clock bus. Selecting means for selecting, wherein the central processing unit outputs a clock signal and a selection signal for selecting a target optical data link to the selecting means, and the selecting means includes the selecting means The clock signal is output only to the target optical data link based on the selection signal, and the optical data link, along with the clock signal, has its own slave address. If the same slave address and less receives a stored data signal as the destination information, and performs capture of the data signal.
[0011]
In this optical transmission apparatus, when the central processing unit outputs a clock signal and a selection signal for selecting a target optical data link to the selection unit, the selection unit selects the target optical data link corresponding to the selection signal. Only output a clock signal. At this time, the selection unit may generate and output an individual clock signal for the target optical data link, or may output a clock signal from the central processing unit.
[0012]
Thereby, the optical data link other than the target optical data link does not receive the clock signal, and only the target optical data link receives the clock signal. When the target optical data link that has received the clock signal receives a data signal in which the same slave address as its own slave address is stored as destination information together with the clock signal, the target optical data link takes in the data signal. Then, for example, a response to the central processing unit and data exchange with the central processing unit are performed.
[0013]
As described above, according to the optical transmission apparatus of the present invention, the selecting means outputs the clock signal only to the target optical data link corresponding to the selection signal from the central processing unit, and receives the clock signal. When a link receives a data signal in which the same slave address as its own slave address is stored along with the clock signal, a configuration in which multiple optical data links are connected to the same communication bus in order to capture the data signal Even so, communication from the central processing unit to the target optical data link can be reliably performed.
[0014]
The optical transmission apparatus of the present invention can be applied to a configuration that further includes devices other than the optical data link as described below. In other words, the optical transmission apparatus according to the present invention is configured in a manner other than the optical data link, which is assigned a slave address different from the common slave address and is connected to the central processing unit via each of a data bus and a clock bus. And when the other device receives a data signal in which the same slave address as the clock signal and its own slave address is stored as destination information from the central processing unit, the data It is characterized by taking in a signal.
[0015]
In this optical transmission apparatus, since a slave address different from a common slave address is assigned to a plurality of optical data links, the data signal for the target optical data link is captured by the other device. In addition, the data signal addressed to the other device is not taken in by any of the optical data links. Therefore, even in a configuration further including devices other than the optical data link, communication from the central processing unit to the target optical data link and communication from the central processing unit to other devices can be reliably performed. it can.
[0016]
The invention relating to the above optical transmission apparatus can also be described as an invention relating to an optical data link control method as follows.
[0017]
That is, the optical data link control method according to the present invention includes a single central processing unit that outputs a data signal in which a slave address of a data transmission destination device is stored as destination information, and the central processing unit via a data bus. And a plurality of optical data links to which a common slave address is assigned, and each optical data link and the central processing unit via a clock bus to select only a target optical data link An optical data link control method in an optical transmission apparatus configured to include a selection unit, wherein the central processing unit outputs a clock signal and a selection signal for selecting a target optical data link to the selection unit The selection means outputs the clock signal only to the target optical data link based on the selection signal, and the optical data link Together with the clock signal, when the slave address identical to the slave address of the self receives the stored data signal as the destination information, the incorporation of the data signal, characterized in that.
[0018]
In this optical data link control method, when the central processing unit outputs a clock signal and a selection signal for selecting a target optical data link to the selection unit, the selection unit selects the target optical data based on the selection signal. When a clock signal is output only to the link, and only the target optical data link that received the clock signal receives a data signal in which the same slave address as its own slave address is stored as destination information along with the clock signal The data signal is taken in.
[0019]
In this way, the clock signal is output only to the target optical data link corresponding to the selection signal from the central processing unit, and the target optical data link that has received the clock signal has the same slave address as that of its own slave address. When a data signal in which a slave address is stored is received, the target optical data link is received from the central processing unit even in a configuration in which a plurality of optical data links are connected to the same communication bus in order to capture the data signal. Can be reliably communicated to.
[0020]
Also, in the optical data link control method according to the present invention, the optical transmission apparatus is assigned a slave address different from the common slave address and is connected to the central processing unit via each of a data bus and a clock bus. The device further includes a device other than the optical data link, and the other device includes a data signal in which the same slave address as the clock signal and its own slave address is stored as destination information. When the data is received from the processing unit, the data signal is fetched.
[0021]
That is, since a slave address different from a common slave address is assigned to a plurality of optical data links, the data signal to the target optical data link is not captured by the other devices, Further, the data signal addressed to the other device is not taken in by any optical data link. Therefore, even if the optical transmission apparatus to which the optical data link control method of the present invention is applied further includes a device other than the optical data link, communication from the central processing unit to the target optical data link, In addition, communication from the central processing unit to other devices can be reliably performed.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of an optical transmission apparatus and an optical data link control method according to the present invention will be described with reference to the drawings.
[0023]
First, the configuration of the optical transmission apparatus 10 will be described with reference to FIG. As shown in FIG. 1, the optical transmission device 10 includes a central processing unit (CPU) 12 and a plurality (N) of optical data links D0, D1,... DN (hereinafter collectively referred to as an optical data link D), The temperature sensor 16, the memory 18, and the selector 14 as selection means for selecting a target optical data link are configured. Among these, the CPU 12 corresponds to a master device, and the optical data link D, the temperature sensor 16 and the memory 18 correspond to slave devices. The CPU 12 performs setting and status monitoring of each slave device such as the optical data link D.
[0024]
Each slave device (each of the optical data link D, the temperature sensor 16 and the memory 18) is connected to the CPU 12 via a serial data line (hereinafter referred to as SDA) 28 for transmitting data signals. Among these, each of the temperature sensor 16 and the memory 18 is directly connected to the CPU 12 via a serial clock line (hereinafter referred to as SCL) 24 for transmitting a clock signal, and each of the optical data links D is connected via the SCL 26. The selector 14 is connected to the CPU 12 via the SCL 20 and a plurality of (for example, three) selection signal lines 22.
[0025]
The CPU 12 selects one target optical data link by a selection signal transmitted to the selector 14 via the selection signal line 22. Specifically, by representing a three-digit binary number by a combination of three selection signals transmitted via the three selection signal lines 22, one optical data link corresponding to the binary number is selected. Can do. For example, it is defined that the three selection signal lines 22 shown in FIG. 2 represent the fourth place bit, the second place bit, and the first place bit in order from the left. The CPU 12 transmits a low level signal to the second line and the second line, a high level signal to the rightmost line, and the selector 12 sends a binary “001” by the combination of the above three signals. And a target optical data link D1 can be selected.
[0026]
Each slave device is assigned a slave address. Here, the same slave address A2h (meaning hexadecimal “A2”, hereinafter the same) is assigned to each optical data link D, and the slave address 96h different from the above is assigned to the temperature sensor 16. 18 is assigned a slave address A0h.
[0027]
Next, processing when the CPU 12 starts communication with the target optical data link D1 will be described with reference to FIGS. Note that FIG. 3 shows the processing contents in the optical transmission apparatus 10 as a flowchart for easy understanding.
[0028]
First, in step S01 of FIG. 3, the CPU 12 outputs a clock signal and a selection signal to the selector 14, and outputs a data signal to each device (optical data link D, temperature sensor 16, memory 18). At this time, the clock signal from the CPU 12 is also output to the temperature sensor 16 and the memory 18 via the SCL 24 branched from the SCL 20. At this time, since the slave address of the target optical data link D1 is A2h, the CPU 12 stores and outputs the information of the slave address A2h in the header portion of the data signal as shown in FIG.
[0029]
In the next step S02, the selector 14 analyzes the information represented by the selection signal received via the three selection signal lines 22 shown in FIG. 2 (that is, the binary number “001” represented by the selection signal), The optical data link D1 is specified as the optical data link, and a clock signal is output only to the target optical data link D1. As a result, the clock signal is output from the selector 14 to the optical data link D1 via the SCL1, and is not output to the other optical data links D. In FIG. 2, the clock signal transmitted to each device is displayed on the data signal. Here, the clock signal is transmitted only to the optical data link D1, the temperature sensor 16, and the memory 18.
[0030]
In the next step S03, each device checks the slave address (A2h in this case) in the header part of the data signal with its own address. As a result, the temperature sensor 16 and the memory 18 determine that the slave address in the header portion does not match its own address, and therefore do not respond to the data signal.
[0031]
In the next step S04, only the optical data link that has received the clock signal and has the same slave address, that is, the optical data link D1 in which the clock signal is transmitted from the selector 14 in the optical data link D, captures the data signal.
[0032]
In the next step S05, communication between the target optical data link D1 and the CPU 12 is executed. That is, as shown in FIG. 2, only the optical data link D1 returns a response signal to the CPU 12, and execution of communication with the CPU 12 is started.
[0033]
Through the processing as described above, the selector 14 newly provided in the optical transmission apparatus 10 outputs the clock signal only to the target optical data link D1 corresponding to the selection signal from the CPU 12, and the target optical data that has received the clock signal. When the link D1 receives a data signal storing the same slave address (A2h) as its own slave address together with the clock signal, the plurality of optical data links D communicate with each other in order to take in the data signal. Even with the configuration connected to the bus, communication from the CPU to the target optical data link D1 can be reliably performed.
[0034]
Even if the optical transmission apparatus 10 includes other devices other than the optical data link D, the other devices include a slave address (96h, different from the slave address (A2h) common to the plurality of optical data links D). A0h) is assigned, the data signal addressed to the target optical data link D1 is not captured by another device, and the data signal addressed to the other device is captured by any one of the optical data links D. It will never happen. Therefore, communication from the CPU to the target optical data link and communication from the CPU to another device can be reliably performed.
[0035]
Furthermore, with the above configuration, there is no problem even if the same slave address is assigned to a plurality of optical data links. Therefore, the manufacturer of the optical data link can set the same slave address to each optical data link at the time of factory manufacture, and the user can There is also an advantage that it is not necessary to change the slave address of the optical data link when the board is mounted. There is also an advantage that setting and status monitoring can be performed by a single master device (CPU) for a plurality of optical data links having the same slave address.
[0036]
1 and FIG. 2 show an example in which three selection signal lines 22 are provided as an example. However, the number of selection signal lines 22 is set according to the number of built-in optical data links D. It may be increased or decreased. Further, the number of selection signal lines 22 is one, and a selection signal (for example, a signal representing a binary number of a plurality of digits by turning on / off of a plurality of pulse trains) from the CPU 12 so that the selector 14 can identify one optical data link of interest. It is good also as a structure which transmits.
[0037]
【The invention's effect】
As described above, according to the present invention, the clock signal is output only to the target optical data link corresponding to the selection signal from the central processing unit, and the target optical data link receiving the clock signal is In addition, when a data signal storing the same slave address as its own slave address is received, in order to capture the data signal, even in a configuration in which a plurality of optical data links are connected to the same communication bus, Communication from the central processing unit to the target optical data link can be reliably performed.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an optical transmission apparatus according to an embodiment of the invention.
FIG. 2 is a diagram for explaining a signal flow when a CPU starts communication with a target optical data link D1.
FIG. 3 is a flowchart showing processing related to serial bus communication in the optical transmission apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Optical transmission apparatus, 12 ... CPU (central processing part), 14 ... Selector (selection means), 16 ... Temperature sensor (other devices), 18 ... Memory (other devices), 20, 24, 26 ... SCL, 22 ... selection signal line, 28 ... SDA, D ... optical data link.

Claims (4)

A single central processing unit that outputs a data signal in which the slave address of the device of the data transmission destination is stored as destination information;
A plurality of optical data links connected to the central processing unit via a data bus and assigned a common slave address;
A selection means connected to each optical data link and the central processing unit via a clock bus to select only a target optical data link;
Comprising
The central processing unit outputs a clock signal and a selection signal for selecting a target optical data link to the selection unit,
The selection means outputs the clock signal only to the target optical data link based on the selection signal,
When the optical data link receives a data signal in which the same slave address as its own slave address is stored as destination information together with the clock signal, the optical data link takes in the data signal.
An optical transmission device characterized by that. The device further includes a device other than the optical data link, which is assigned a slave address different from the common slave address and is connected to the central processing unit via each of a data bus and a clock bus,
The other device fetches the data signal when receiving from the central processing unit a data signal in which the same slave address as the clock signal and its own slave address is stored as destination information. The optical transmission device according to claim 1. A single central processing unit that outputs a data signal in which a slave address of a data transmission destination device is stored as destination information, and is connected to the central processing unit via a data bus, and is assigned a common slave address. In an optical transmission apparatus comprising a plurality of optical data links and a selection means connected to each optical data link and the central processing unit via a clock bus for selecting only a target optical data link An optical data link control method comprising:
The central processing unit outputs a clock signal and a selection signal for selecting a target optical data link to the selection means;
The selection means outputs the clock signal only to the target optical data link based on the selection signal,
When the optical data link receives, together with the clock signal, a data signal in which the same slave address as its own slave address is stored as destination information, the data signal is captured.
An optical data link control method. The optical transmission apparatus further includes a device other than the optical data link, which is assigned a slave address different from the common slave address and is connected to the central processing unit via each of a data bus and a clock bus. Consists of
The other device fetches the data signal when the data signal in which the same slave address as the clock signal and its own slave address is stored as destination information is received from the central processing unit.
4. The optical data link control method according to claim 3, wherein:

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