JPH07183935A - Method and device for synchronous transmission and reception - Google Patents

Abstract

PURPOSE:To reduce memory capacity for communication processing and increase the communication speed. CONSTITUTION:A main station A and a slave station B are connected by a 1st transmission line L1 used for transmission from the main station to the slave station, a 2nd transmission line L2 used for transmission from the slave station to the main station, and a clock transmission line L3 used for transmission of a clock signal. The main station actively sends commands and data to the slave station, which is requested by the main station to passively send data to the main station. The main station performs both the transmission of the data to the slave station and the reception of the data from the slave station in synchronism with the clock signal at the time of data transfer without reference to whether the master station sends the data to the slave station or receives the data from the slave station.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a synchronous type in which a master station actively transmits commands and data to slave stations, and slave stations passively transmit data to master stations when requested by the master station. The present invention relates to a transmission / reception method and an apparatus thereof.

[0002]

2. Description of the Related Art Conventionally, a first transmission line used for transmission from a master station to a slave station, a second transmission line used for transmission from a slave station to a master station, and a clock transmission used for transmission of a clock signal. The master station actively transmits commands and data to the slave stations.
In a synchronous transmission / reception device in which a slave station passively transmits data to the master station when requested by the master station, the master station includes a master station transmission / reception processing program which is software.

The master station transmission / reception processing program provided in this master station is executed when the master station transmits data to the slave station and when the master station receives data from the slave station. The main station reception processing program is included. Moreover, the main station transmission processing program and the main station reception processing program are independent and independent programs.

FIG. 6 is a flowchart showing the main station transmission / reception processing program as described above. The transmission / reception processing procedure between the master station and the slave stations will be described below with reference to the flowchart of FIG. That is, when the master station tries to start communication with the slave station, the master station executes step 100 and requests the slave station to select whether to transmit data or receive data from the slave station. .

At this time, if the master station wants to transmit to the slave station, the master station executes step 200,
A command (an instruction for a slave station, such as "Please send data, please receive it", which is usually composed of 8 bits) is stored in the transmission register of the master station.
After that, the master station executes step 201 to output the unit clock signal from the clock transmission port of the master station to the clock reception port of the slave station via the clock transmission path, and
Step 202 is executed to output the first bit of the command from the transmission port of the master station to the reception port of the slave station via the first transmission line.

Thereafter, the master station executes step 203 to judge whether or not all the bits of the command have been transmitted,
If all the bits of the command have not been transmitted, the steps 201, 202, and 203 are repeatedly executed, and the transmission of all the bits of the command is completed, such as the second bit of the command, the third bit of the command, .... And step 2
Execute 04.

The master station executing step 204 stores the data to be transmitted to the slave stations in the transmission register. After that, the master station executes step 205 to output the unit clock signal from the clock transmission port of the master station to the clock reception port of the slave station via the clock transmission path, and at the same time, to execute step 2
Step 06 is executed to output the first bit of the data from the transmission port of the master station to the reception port of the slave station via the first transmission line.

After that, the main station executes step 207 to determine whether or not all the bits of the data have been transmitted. If the transmission of all the bits of the data has not been completed, the main station repeatedly executes steps 205, 206 and 207. Then, the second bit of data, the third bit of data, ... In this way, the master station serves the purpose of transmitting data to the slave stations.

By the way, if the master station wants to receive data from the slave station, the master station performs step 100 and then step 300 to send a command ("this data Command, which normally consists of 8 bits). After that, the main station proceeds to step 301
To output the unit clock signal from the clock transmission port of the master station to the clock reception port of the slave station via the clock transmission line, and execute step 302 to execute the first bit of the command via the first transmission line. Is output from the transmission port of the master station to the reception port of the slave station.

Thereafter, the master station executes step 303 to judge whether or not all the bits of the command have been transmitted,
If all the bits of the command have not been transmitted, the steps 301, 302, 303 are repeatedly executed, and the transmission of all the bits of the command is finished, such as the second bit of the command, the third bit of the command, .... And step 3
Execute 04.

The master station executing step 304 outputs the unit clock signal from the clock transmitting port of the master station to the clock receiving port of the slave station via the clock transmission path, and executes step 305 to execute the second transmission path. The first bit of the data transmitted from the transmission port of the slave station to the reception port of the master station via is received and stored in the reception register of the master station.

After that, the main station executes step 306 to judge whether or not all the bits of the data have been received. If all the bits of the data have not been received, the main station repeatedly executes steps 304, 305 and 306. Then, the second bit of data, the third bit of data, ... In this way, the master station serves the purpose of reading and receiving predetermined data from the slave stations.

That is, as can be understood from the above description, the main station transmission processing program (steps 200 to 20)
7) and main station reception processing program (steps 300 to 30)
6) is a separate program that is independent of each other.

FIG. 7 is an explanatory diagram showing the operation timings of the transmission port of the main station and the reception port of the main station.
7A shows a case where the master station transmits data to the slave station, and FIG. 7B shows a case where the master station receives data from the slave station. It can be seen from FIG. 7 that the operation modes of the transmission port of the master station and the reception port of the master station are different when the master station transmits data to the slave station and when the master station receives data from the slave station. It can be understood. That is, in the case of FIG. 7A in which the master station transmits data to the slave station, the master station transmission port operates for both commands and data, and the master station reception port for commands. It also does not work on data. However, the master station receives data from the slave stations.
In the case of (b), the transmission port of the main station operates for commands but does not operate for data, and the reception port of the main station does not operate for commands but operates for data. To do.

FIG. 8 is an explanatory diagram showing the communication processing time.
In FIG. 8, the communication processing time t is the command storage time (processing time of Step 200 or Step 300) t ₁ and the command transmission time (processing time until exiting Step 201 to Step 203 or Step 301 to Step 303). processing time) t ₂ until escape, data storage time (processing time) t ₃ in step 204, the data transmission time or a data reception time (step 205 to process time to escape step 207 or step 304
~ Processing time until exiting step 306) t ₄ is added respectively. Also,
FIG. 8 shows that the transmission / reception selection time (processing time of step 100) t ₀ is required before communication is started.

[0016]

Therefore, the main station transmission / reception processing program of the conventional synchronous transmission / reception device is composed of a main station transmission processing program and a main station reception processing program which are independent programs. As a result, the memory capacity for the program becomes large, and when the master station tries to start communication with the slave station, data is transmitted to the slave station or data is transmitted from the slave station. Since it is necessary to request selection of whether to receive, there is a problem that the communication speed becomes slower by the processing time for the selection.

The present invention has been made to solve the above problems, and an object of the present invention is to reduce the memory capacity for a communication processing program and to increase the communication speed. Another object is to provide a synchronous transmission / reception method and its device.

[0018]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a master station and a slave station which are used for transmission from the master station to the slave station. One transmission line, a second transmission line used for transmission from the slave station to the master station, and a clock transmission line used for transmission of a clock signal are connected, and the master station sends commands and data to the slave station. In a synchronous transmission / reception method in which the slave station passively transmits data to the master station when requested by the master station, the master station, even when transmitting data to the slave station, Even when receiving data from a slave station, at the time of data transfer, the transmission of data to the slave station and the reception of data from the slave station are performed in pairs in synchronization with the clock signal. Is characterized by.

According to another aspect of the invention, the master station and the slave station have a first transmission path used for transmission from the master station to the slave station and a second transmission path used for transmission from the slave station to the master station. Connected by a clock transmission line used for transmitting a clock signal, the master station actively transmits commands and data to the slave stations, and the slave stations are requested by the master station. In a synchronous transmission / reception device that passively transmits data to the master station, the master station, even when transmitting data to the slave station, when receiving data from the slave station, At the time of data transmission / reception, the data transmission / reception means is provided for performing transmission of data to the slave station and reception of data from the slave station as a pair in synchronization with the clock signal.

[0020]

As described above, according to the first aspect of the present invention, the master station does not matter whether the master station transmits data to the slave station or receives data from the slave station. At the time of data transmission / reception, it is a method in which data transmission to a slave station and data reception from a slave station are performed as a pair in synchronization with a clock signal. Therefore, the transmission processing procedure when the master station transmits data to the slave station and the reception processing procedure when the master station receives data from the slave station do not have to be independent programs, but should be common. You can Further, it is not necessary to confirm whether to transmit data or receive data when the main station starts communication and to switch the program to be executed according to the confirmation result.

Further, in the invention according to the second aspect, even when the master station transmits data to the slave station,
Even when receiving data from a slave station, at the time of data transfer, a data transfer means for performing paired data transmission to the slave station and reception of data from the slave station in synchronization with the clock signal is provided. Be prepared. Therefore, it has the same effect as the invention according to claim 1.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the synchronous transmission / reception method and apparatus according to the present invention will be described in detail below with reference to FIGS. FIG. 1 is a block diagram showing a synchronous transmission / reception device. FIG. 2 is a flow chart for explaining the data transfer means of the main station. FIG. 3 is a flow chart for explaining the operation of the slave station. FIG. 4 is an explanatory diagram showing operation timings of the transmission port of the main station and the reception port of the main station, and FIG.
Shows the case where the master station transmits data to the slave station.
(B) shows the case where the master station receives data from the slave station. FIG. 5 is an explanatory diagram showing the communication processing time of the synchronous transmission / reception device.

As shown in FIG. 1, the synchronous transmission / reception apparatus includes a master station A and a slave station B. The main station A includes a transmission register A ₁ , a reception register A ₂ , a control unit A _3, and a clock generation unit A ₄ . The slave station B includes a transmission register B ₁ , a reception register B _2, and a control unit B ₃ . The master station A and the slave station B are connected by a _first transmission line L ₁ , a second transmission line L _2, and a clock transmission line L ₃ . The first transmission line L ₁ is a transmission port _AT of the master station A and a reception port B of the slave station B.
It is connected to _R. The second transmission line L ₂ connects the reception port A _R of the master station A and the transmission port B _{T of the} slave station B. The clock transmission line L ₃ connects the clock transmission port A _C of the master station A and the clock reception port B _{C of the} slave station B.

The transmission register A ₁ is a shift register portion for storing the command or the data immediately before the master station A transmits to the slave station B bit by bit in units of 1 byte. The reception register A ₂ is a shift register portion that stores the data received by the master station A from the slave station B bit by bit in 1-byte units. The control unit A ₃ operates with the clock signal from the clock generation unit A ₄ , and controls the transmission register A ₁ and the reception register A ₂ .

When the master station A transmits a data request command to the slave station B, the transmission register B ₁ stores the data immediately before the slave station B transmits to the master station A bit by bit, byte by byte. This is the shift register part to store in. The reception register B ₂ is a shift register portion that stores the data received by the slave station B from the master station A bit by bit when the master station A sends a data transmission command to the slave station B in 1-byte units. . The control unit B ₃ is operated by the clock signal output from the clock generation unit A ₄ via the clock transmission line L ₃ , and controls the transmission register B ₁ and the reception register B ₂ .

In the synchronous transmitter / receiver configured as described above, the master station A exchanges data with the slave station B as follows. That is, as shown in FIG.
Whether transmitting data to the slave station B or requesting data from the slave station B, first, step 50
0 is executed and the control unit A ₃ stores the command in the transmission register A ₁ . The command stored in the transmission register A ₁ is a data transmission command ("I will send data from now on, please receive it") when transmitting data to the subordinate station B. When requesting data, a data request command ("send this data") is issued.

After executing step 500, the master station A then executes step 501 to output the unit clock signal to the control unit B ₃ of the slave station B via the clock transmission line L ₃ and also executes step 502. the first through the transmission line L ₁ outputs the first bit of the command from the sending port a _T of the main station a to the reception port B _R of the slave station B to.

Thereafter, the main station A executes step 503, and the control section A ₃ judges whether or not all the bits of the command stored in the transmission register A ₁ in step 500 have been transmitted, and the command If all bits have not been transmitted, steps 501, 502, and 503 are repeatedly executed, and the second bit of the command, the third bit of the command, ...
When all the bits of the command have been transmitted as in the case of "...", step 504 is executed.

The master station A which executes step 504 stores the data to be transmitted to the slave station B in the transmission register A ₁ by the control section A ₃ . At this time, if the commands data transmission command stored in the transmission register A ₁ in step 500, although data stored in the transmission register A ₁ in step 504 is present data, the transmission register A ₁ in step 500 If the stored command is a data request command, the data stored in the transmission register A ₁ in step 504 is invalid data (dummy data).

Thereafter, the master station A executes step 505.
Then, the clock transmission line L₃A unit clock signal via
Clock transmission port A of main station A_CTo control unit B of slave station B
₃The master station A executes step 506
Control unit A₃Thus, in step 504, the transmission register A
₁The first bit of the data stored in the first transmission line L ₁
Transmission port A of main station A via_TFrom slave station B reception port
To B_ROutput to. At the same time, the main station A makes a step 50
7 to execute the control unit A₃Causes slave station B to send port B
_TTo reception port A of main station A_RReceive data to output to
And receive register A₂To store. At this time, step
Send register A at 500₁The commands stored in
If it is a data transmission command, master station A receives it in step 507.
The received data is invalid data (dummy data)
In step 500, the transmission register A₁Stored in
If the command is a data request command, master station A
The data received in step 507 is this data.

Thereafter, the main station A executes step 508, and the control section A ₃ judges whether or not all the bits of the data stored in the transmission register A ₁ in step 504 have been transmitted, and If all bits have not been transmitted, steps 505, 506 and 507 are repeatedly executed,
The second bit of data, the third bit of data, and so on ...

In this way, the master station A serves the purpose of transmitting data to the slave station B or the purpose of receiving data from the slave station B. Moreover, although the master station A transmits data to the slave station B or reads and receives data from the slave station B, there is a difference between this data and invalid data The main station transmission program and the main station reception program can be commonly used.

That is, the master station transmission / reception program can be unified as shown in the flow chart of FIG. 2, and the transmission processing procedure when the master station transmits data to the slave station and the master station receives data from the slave station. In the case of the reception processing procedure,
They do not have to be independent programs and can be shared. Therefore, the memory capacity for the main station transmission / reception program, which is software, can be small. In addition, it is not necessary to confirm whether the main station A transmits data or receives data when starting communication, and it is not necessary to switch the program to be executed according to the confirmation result. You can speed it up.

A method of exchanging data between the slave station B and the master station A will be described below with reference to FIG. That is, as shown in FIG. 3, the slave station B executes step 600 to monitor the presence or absence of the clock signal from the master station A.
Upon receiving the clock signal, the slave station B executes step 601 to receive 1 bit of the command transmitted by the master station A and store it in the reception register B ₂ . After that, the slave station B executes step 602, judges whether or not all the bits of the command transmitted by the master station A (in this embodiment, the command is configured in 1-byte units) have been received, and the command is transmitted. If all the bits of the command have not been received, steps 600, 601, and 602 are repeatedly executed, and the reception of all the bits of the command is completed, such as the second bit of the command, the third bit of the command, ....

Slave station B which has received all the bits of the command
Performs step 603 and steps 600, 60
1, 602 is executed to analyze the meaning of the received command. Then, the slave station B executes step 604, and whether the command means a data transmission command ("I will send data, please receive it.") Or a data request command ("Please send this data." Please "). The slave station B proceeds to step 700 if the command analysis result in step 603 is a data transmission command, and proceeds to step 8 if the command analysis result in step 603 is a data request command.
Go to 00.

The slave station B which has proceeded to step 700 is the master station A.
The presence / absence of the clock signal is monitored. When the clock signal is received, step 701 is executed, and 1 bit of the data transmitted by the main station A is received and stored in the reception register B ₂ . Thereafter, the slave station B executes step 702,
It is judged whether or not all the bits of the data transmitted by the main station A (in this embodiment, the data is configured in 1-byte units) have been received, and if all the bits of the command have not been received, a repeating step is performed. 700, 701, 702 are executed, the second bit of data, the third bit of data, ...
Finish receiving all the bits of the data. After that, when the slave station B finishes receiving all the bits of the data, it executes step 703 to perform the processing based on the received data, and then proceeds to step 600 again and repeats the same processing.

The slave station B which has proceeded to step 800 is
Based on the command analysis result in step 603, master station A
Create data for replying where you want,
The data is stored in the transmission register B ₁ . Then, the slave station B proceeds to step 801 and monitors the presence or absence of a clock signal from the master station A. When the clock signal is received, the slave station B executes step 802, and sets ₁ of the data stored in the transmission register B ₁ at step 800. Transmit bits from transmit port B _T. After that, the slave station B executes step 803, determines whether the slave station B has transmitted all the data to be transmitted requested by the master station A, and the transmission of the data to be transmitted is not completed. If so, steps 800, 801, 802 until the transmission of the data to be transmitted is completed.
803 is repeatedly executed, and finally the process proceeds to step 600 to repeat the same processing.

As is apparent from the above description, the above
The synchronous transmitter / receiver configured as shown in FIG.
When the master station A transmits data to the slave station B,
When the master station A receives data from the slave station B.
Shin Port A_TAnd receiving port A _RThe same way of operation with
I understand that there is. That is, master station A
In the case of FIG. 4 (a) for transmitting data, the transmission port of the main station A is
To A_TWorks for commands and data,
Reception port A of main station A_RData is invalid data
However, although it does not work for commands,
Then it works. Similarly, master station A receives data from slave station B
In the case of FIG. 4B for receiving the data, the transmission port of the main station A
A_TData is invalid data, but
However, it also operates on data, and reception port A of main station A
_RDoes not work for commands but
Then it works.

The communication processing time of the synchronous transmission / reception apparatus configured as described above is as shown in FIG. That is, the communication processing time t is the command storage time (step 5
00 processing time) t ₁ and command transmission time (processing time until exiting from step 501 to step 503) t
₂ and data storage time (processing time of step 504) t
₃ and data transmission time or data reception time (processing time until the process exits from step 505 to step 508) t
_This is the time when ₄ and ₄ are added together. Moreover, the main station A
Always repeats the communication processing procedure according to the flowchart shown in FIG. 2, so that the transmission / reception selection time (step 1) shown in FIG.
00 processing time) t ₀ becomes unnecessary, and this processing time t ₀
Can be shortened and the communication processing speed can be increased.

[0040]

The synchronous transmission / reception method and apparatus of the present invention are the above-mentioned method and apparatus. According to the invention of claim 1, a transmission process when the master station transmits data to the slave station. Since the procedure and the reception processing procedure when the master station receives data from the slave station can be made common, excellent synchronization that can reduce the memory capacity for the communication processing program and increase the communication speed In the invention according to claim 2, there is an effect that a type transmission / reception method can be provided, and a transmission processing procedure when the master station transmits data to the slave station and a transmission processing procedure when the master station receives data from the slave station Since it can be shared with the reception processing procedure, it is possible to provide an excellent synchronous transmission / reception device that can reduce the memory capacity for the communication processing program and increase the communication speed. The effect to say.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a synchronous transmission / reception device according to the present invention.

FIG. 2 is a flow chart for explaining a data transfer means of a main station of the synchronous transmission / reception device.

FIG. 3 is a flowchart illustrating an operation of a slave station of the synchronous transmission / reception device.

FIG. 4 is an explanatory diagram showing operation timings of a transmission port of a main station and a reception port of the main station of the synchronous transmission / reception device.

FIG. 5 is an explanatory diagram showing communication processing time of the synchronous transmission / reception device.

FIG. 6 is a flowchart showing a transmission / reception processing program of a main station of a conventional synchronous transmission / reception device.

FIG. 7 is an explanatory diagram showing operation timings of a transmission port of a main station and a reception port of the main station of a conventional synchronous transmission / reception device.

FIG. 8 is an explanatory diagram showing communication processing time of a conventional synchronous transmission / reception device.

[Explanation of symbols]

A master station B slave station L ₁ first transmission line L ₂ second transmission line L ₃ clock transmission line

Claims (2)

[Claims] 1. A master station and a slave station include a first transmission path used for transmission from the master station to the slave station, a second transmission path used for transmission from the slave station to the master station, and a clock signal transmission. The master station actively transmits commands and data to the slave station, and the slave station passively transmits data to the master station when requested by the master station. In the type transmission / reception method, the master station synchronizes with the clock signal and transmits / receives data to / from the slave station regardless of whether the master station transmits data to the slave station or receives data from the slave station. A method for transmitting and receiving data to and from a slave station is performed as a pair. 2. The master station and the slave station are a first transmission path used for transmission from the master station to the slave station, a second transmission path used for transmission from the slave station to the master station, and a clock signal transmission. The master station actively transmits commands and data to the slave station, and the slave station passively sends data to the master station when requested by the master station. In a synchronous transmission / reception device that transmits data, the master station transmits the data to the slave station, receives the data from the slave station, and transmits or receives the data. 1. A synchronous transmission / reception device, comprising: data transmission / reception means for performing paired transmission of data to a slave station and reception of data from a slave station in synchronization with a signal.