JPH03250217A - Control circuit for character string display device - Google Patents

Abstract

PURPOSE:To make correspondence only by changing the number of reception circuits to be annularly arranged corresponding to the number of microprocessors by circularly connecting plural reception circuits and a character string display driving circuit. CONSTITUTION:In the microprocessor of a picture controller, control circuits 1 output data from data communicating lines 2 to reception circuits 3 and 4 synchronously with picture synchronizing signals. Independently of this data output, the data communication lines circularly connected with the reception circuits 3 and 4 and a display driving circuit 5 are controlled in prescribed procedures so as to control the circular data transfer. Thus, it is not necessary to design the switching circuit of a bus when increasing or decreasing the microprocessors for device control, etc., to output display character string data, and the correspondence can be made only by changing the number of reception circuits to be annularly arranged corresponding to the number of microprocessors.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a character string display control circuit, and in particular to a character string display control circuit that receives character string display data from a plurality of microprocessors and outputs this character string to a display. The present invention relates to a column display control circuit.

[Conventional technology]

Conventionally, this type of character string display control circuit includes a switching circuit that switches the control bus from each microprocessor, and an F
The received data storage circuit by the IFO device and this F
It consisted of a microprocessor circuit that read display character string data from the IFO device and drove the display.

Next, regarding an example of a conventional character string display control circuit, N
This will be explained with reference to FIG.

In FIG. 2, 1 is a control circuit by a microprocessor of the video adjustment device, 2 is a data communication line, 7 is a switching circuit for a control bus of the microprocessor, 8 is a received data storage circuit by a FIFO device, and 9 is a microprocessor-based control circuit. The display drive circuit 6 is a character string display.

The control circuit 1 of the video adjustment device controls one of the video output from the device.
Since it is necessary to control the state of the device for each field, control data is output in synchronization with the synchronization signal. For this purpose, the control circuit 1 inputs the video synchronization signal to itself, refers to it, and outputs the control data. In addition to performing the output, each of the operator's references! I also control the Ii display. The control circuit 1 controls the switching circuit 7 from the data communication line 2 in synchronization with the video synchronization signal, and outputs all data of the character string to be displayed to the storage circuit 8. The display drive circuit 9 reads the data written to the storage circuit 8 and drives the character string display 6.

[Problem to be solved by the invention]

The conventional character string display control circuit described above has a switching circuit for controlling the control buses of multiple microprocessors, and the number of input terminals of this switching circuit corresponds to the number of microprocessors. When increasing or decreasing the number of microprocessors depending on the scale of the device used, there is a drawback that bus switching circuits must be designed accordingly.

[Means to solve the problem]

The character string display control circuit of the present invention has first and second input terminals and a first output terminal, respectively, and inputs character string data input from the second input terminal into character string data input from the first input terminal. a plurality of receiving circuits that add character string data and output it from the first output terminal, a third input terminal, and I! When character string data is input from the third input terminal, the input character string data is displayed on the character string display, and the output terminal is output from the second output terminal.
a character string display drive circuit that outputs character string data, and each of the first output terminals is connected to either one of the second input terminals or one of the third input terminals. and each of the second input terminals is connected to either one of the first output terminals or one of the second output terminals to drive the plurality of receiving circuits and the character string display driving circuit. It is connected in a ring.

〔Example〕

Next, the present invention will be explained with reference to the drawings. 1st
The figure is a block diagram of an embodiment of the present invention, and shows an example of a case where the image adjustment device has two microprocessors for controlling the device.

In FIG. 1, 1 is a control circuit using a microprocessor of the video adjustment device, 2 is a data communication line, 3 and 4 are receiving circuits for display character string data, 5 is a display drive circuit using a microprocessor, and 6 is a character string display. It is a vessel.

A microprocessor-based control circuit 1 of the video adjustment device outputs data from a data communication line 2 to receiving circuits 3 and 4 in synchronization with a video synchronization signal.

Independently of this, the receiving circuits 3 and 4 and the display drive circuit 5 control the data communication line connected in a circular manner according to the procedure described above, and perform circular data transfer control.

First, the display drive circuit 5 sends character string data of to the reception circuit 3. When the receiving circuit 3 receives the character string data from the display drive circuit 5, it adds all the display character string data received from the control circuit 1 to this character string data and outputs it to the receiving circuit 4.

Similarly to the receiving circuit 3, when the receiving circuit 4 receives character string data from the receiving circuit 3, it adds the display character string data received from the control circuit 1 to this character string data and outputs it to the display drive circuit 5. The display driving circuit 5 is connected to the receiving circuits 3 and 4.
The character string display device 6 is driven by the display character string data received via The data from the circuit 1 is sequentially outputted to the character string display 6.

〔Effect of the invention〕

As explained above, the present invention allows each of a plurality of receiving circuits to receive display character string data from a microprocessor and all display character string data from another receiving circuit, and to combine these data into another display string data. Two or more receiving circuits that are connected in a ring to send data to the receiving circuit, and connected in the same way as this ring trap receiving circuit, are used to receive display character string data and send the next one on the ring. By having a display drive circuit that outputs character string information to the receiving circuit and fully controls the character string display using the display character string data, the entire microprocessor for controlling the device that outputs the display character string data can be used. Even if the number of microprocessors is increased or decreased, there is no need to design a bus switching circuit, and this can be handled simply by changing the number of receiving circuits arranged in a ring according to the number of microprocessors.

[Brief explanation of drawings]

FIG. 81 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of an example of a conventional display control circuit. DESCRIPTION OF SYMBOLS 1... Control circuit by microprocessor of video adjustment device, 2... Data communication line, 3.4... Receiving circuit, 5... Display drive circuit, 6... Character string display.

Claims (1)

[Claims] The first input terminal has first and second input terminals and a first output terminal, and adds the character string data input from the second input terminal to the character string data input from the first input terminal. It has a plurality of receiving circuits that output from output terminals, a third input terminal, and a second output terminal, and when character string data is input from the third input terminal, the input character string data is displayed on a character string display. and the second
a character string display drive circuit that outputs empty character string data from the output terminals of the respective first output terminals, and connects each of the first output terminals to one of the second input terminals or one of the third input terminals. either one of the first output terminals or the second input terminal.
A character string display control circuit, wherein the plurality of receiving circuits and the character string display drive circuit are connected to one of the output terminals of the character string display control circuit in a ring shape.