JPS5962936A - Bus common connecting system of plural microcomputer - Google Patents

Abstract

PURPOSE:To connect plural computers to a common bus by transmitting a signal inhibiting the use of bus of an opposite device only when a signal representing the use of bus is not outputted from an opposite computer to prevent the simultaneous use of the use with a simple constitution. CONSTITUTION:The 1st and the 2nd microcomputers 1, 2 transmitting data mutually are provided with ports P14, P24 connecting a data bus DB in common, ports P15, P25 deciding the priority to the use of the bus DB, and ports P16, P26 and P17, P27 outputting a signal representing the usage state of the bus DB. The transmission of data is executed only when a signal representing the use of the bus DB is not generated from the opposite computer to the ports P16, P26, P17, P27. Further, when the use of the bus DB is generated, the port having higher priority transmits data according to the priority of the ports P15, P25 and the other computer waits for the processing until the data transmission is finished.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a common connection system used for mutually using data in a system using a plurality of microcomputers.

In recent years, with the development of microcomputers, microcomputers have been used in various devices, and in particular, in devices that process a large amount of data or devices that require processing of data that occurs simultaneously, multiple microcomputers are used. Treatment is carried out using In this case, each microcomputer controls the external device it is responsible for by operating independently of each other, but in order to unify the control operations as a whole, There often arise cases in which it is desired to transfer data between microcomputers. In this case, it would be fine if the data nodes of the microcomputers were connected to each other, but this would cause an inconvenience at times other than when transferring data5. High-precision timing adjustment is required between the microcomputers so that they are not used. This timing adjustment is good when the number of external devices controlled by each microcomputer is small, but when there are many external devices, this timing adjustment becomes extremely complicated and extremely difficult. In such cases, timing adjustment becomes impossible.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a common connection system for a plurality of microcomputers that prevents common use of a node when two microcomputers are interconnected.

Hereinafter, a detailed explanation will be given using the drawings.

FIG. 1 is a circuit diagram showing an embodiment of a common connection method for a plurality of microcomputers according to the present invention. In the figure, 1 and 2 are the first nodes that require mutual data transfer.
．． Ports pH~P13+P21~P23, which are the second microcomputer and generate control signals to control the terminals that it is in charge of, and ports Ff'nPz and P to which the data bus DB are commonly connected.
'24, port P16 + P2R that sets the priority for the use of data bus DB, and data bus T)
Indicates that port B is in use.
In this case, in order to give the first microcomputer 1 a higher priority than the second microcomputer 2, 1 port Pt5f':i: Connected to ground and becomes P0#, port P2 of the second microcomputer 2
5 is connected to the power supply +V and becomes P1#. Also,
The first microcomputer 1 and second microcomputer 2's path connection host groups P141 to P24 are commonly connected to each other by a data node DB. Terminal groups X and Y respectively handled by the second microcomputer 1.2 are connected. Port P17 of the first microcomputer 1 is connected to port P26 of the second microcomputer 2, and port P27 of the second microcomputer 2 is connected to port P1 of the first microcomputer 1.
6.

The operation of the above configuration will be explained and explained below using the flowchart shown in FIG. Here, when the first microcomputer 1 uses the data bus L)B, fl-t
, t In step ST shown in FIG. 2, the port PI
Determine the state of 6. Then, the second
If a 0" signal indicating that the data DB is in use is being supplied from the port P27 of the microcomputer 2, the system waits until the use of the data DB is about to end. Then, the determination in step ST is If so, it is assumed that the second microcomputer 2 has finished using the data bus DB, and the process moves to step ST2.In step 3 l112, the first microcomputer 1 sets the port P17 to 0. ” to disable the use of the data database on the second microcomputer 2.
shown against.

Then, once the process of step sT2 is finished,
By proceeding to step ST3 and determining the port P16, the first. This prevents the second microcomputers 1 and 2 from simultaneously using the data node DB. That is, in step ST3, port P+6
is set to o'', the data bus DB is used simultaneously, so the process moves to step sT4 to determine the priority 111i.In this case, the port Pts of the first microcomputer l is connected to the ground. connected to
It has a higher priority than the first microcomputer 2. Therefore, in step sT4, the determination result is always YES and the process moves to step 5T11, whereby data bus DB is used and control signals generated from ports P■ to Pta are used. Various controls for the terminals handled by the first microcomputer 1 or data transmission to the second microcomputer 2 are executed. And this data bus DB
When the use of the data DB is finished, in step ST6, the PI3 is set to 11'' to supply a signal indicating that the use of the data database is finished to the second microcomputer 2, and then the end signal is sent. In addition, the first microcomputer 1
If it is set to 'IH, the determination in step ST4 becomes YES and the process moves to step ST7. In step ST, the path of port F'ty is
By clearing the set and forcibly setting it to '1', the data/database DB is used and the process returns to step STl. Therefore, in this case, port P1.
As a result, the data bus DB of the first microcomputer 2
The transition to step STs and the use of the data nozzle DB of the first microcomputer 1 cannot be performed until the use of the first microcomputer 1 is completed. The usage priority of the DB will be low. 1s,
The operation of the second microcomputer 2 shown in FIG. 1 in which P, , and P are connected to the power supply +V is the same as this.

FIG. 3 is a circuit diagram showing another embodiment of the present invention, in which the same parts as in FIG. 1 are indicated using the same symbols. The differences in this figure from Figure 1 are: 1" Pis,
The priority setting by Pel+ is removed, and the signal indicating the use of the data node D I3 generated from port P27 of the second microcomputer 2 and the signal generated from ports P and 7 of the first microcomputer 1 are inverted. By providing an OR gate 3 that calculates the logical sum of the signals and supplies it to the port PI 3 of the first microcomputer 1, the data node DB of the second microcomputer 1 is provided.
This is because the second microcomputer 2 is given higher priority for use.

In the circuit configured in this way, the first. When the second microcomputers 1 and 2 generate a ``0'' signal indicating the use of the data node DB from PI3 + P27, the output of the OR gate 3 becomes 1''. Therefore, the output of the second microcomputer 2 becomes 'Pffi6 becomes "O", but j9-toptg of the first microcomputer 1
is forcibly set to "1". For this reason, when both microcomputers request the use of the data bus I) 13 at the same time, priority is forcibly given to them by the OR gate 3. The operation flowchart of the first microcomputer 1 in this case is as shown in FIG.
will be the same.

As explained above, in the common path connection method for multiple microcomputers according to the present invention, a signal indicating the use of a path is generated only when a signal indicating the use of the path is not generated from the microcomputer on the other side. If Nonosu is used after prohibiting the use of Nonosu by supplying it to the other party's 111j O microcomputer, and both microcomputers simultaneously generate a signal indicating the use of Nonosu, the predetermined The path is used according to the priority order from iL to iL. Therefore, when the paths of a plurality of microcomputers are connected in common, simultaneous g4Q use of nodes can be reliably prevented with a simple configuration of 1-4.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the common connection method for multiple microcomputers according to the present invention, and FIG. 2 is a td@
1 is a flowchart showing the operation of the circuit shown in FIG. It is a flowchart showing the operation. 1...First microcomputer, 2...Second microcomputer, 3...Oracle), I) B...
Data nodes, X, Y...terminal devices. Applicant: ShinNippon Electric Co., Ltd.

Claims (1)

[Claims] (1) The first . In the system having the second microcomputer, the first.
The second microcomputer transmits data to the terminal or the other microcomputer via the node only when the other microcomputer does not generate a signal indicating the use of the node, indicating the use of the node. If the signals are generated at the same time, the microcomputer with a predetermined higher priority uses the node first, and the other microcomputer indicates that the higher priority microcomputer is using the node. A common connection method for multiple microcomputers that waits until the signal is disconnected.