JPH11184792A - Device for writing data in display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and quickly realize the writing of a command and the writing of display data in a fluorescent display tube only by one time of issue of an input and output command signal. SOLUTION: This device is provided with a flip flop 9 for generating a command/data switching signal for selectively switching and storing data transmitted from a microprocessor 1 in a command register 6 or a display register 7 by inputting an input and output command signal for display. A writing signal whose timing is adjusted to the specification of a display based on the input and output command signal for display by a timing adjusting circuit 11 is generated. Then, the data from the command register 6 or the display register 7 are written in the display based on the writing signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data writing device for a display used to write commands and display data on a display such as a fluorescent display tube.

[0002]

2. Description of the Related Art Fluorescent display tubes are widely used for interest rate display boards of banks and public notice devices because they have the lowest unit price per dot as a display element. Further, in such a display, a plurality of fluorescent display tubes are usually arranged side by side so that a plurality of symbols such as characters and numerals can be displayed thereon. The external control circuit for controlling the display and the number of interface cores connecting the fluorescent display tubes greatly affect the reliability and cost reduction of the display device.

The display usually transmits display data from an external control device to the fluorescent display tube module via an address bus and a data bus. In this case, in order to reduce the crosstalk of each display data, an interface bus and a data bus are arranged for each fluorescent display unit while avoiding interface core wires having different properties. In this case, the number of used signal lines and the number of connection cables are greatly increased, and the connection portion is complicated, and the work of wiring check becomes troublesome.

On the other hand, there has been proposed a data writing device for a display comprising an external control circuit shown in FIG. 3 and a fluorescent display module 26 shown in FIG. First, the external control circuit will be described. 1 is a microprocessor for outputting a command, display data and an address.
Is a data output input / output (I / O) command 19, a command / data (C / D) switching input / output (I / O) command 20, based on the output data of the microprocessor 1,
The decoder generates a data / command write (WR) signal. The command is data relating to switching of a display screen, luminance setting, and the like. Reference numeral 4 denotes a CPU including the display data output from the microprocessor 1.
Data. Reference numeral 22 denotes a flip-flop driver which operates using the CPU data 4 and the data output input / output command 19 as inputs, and 23 denotes a CPU data 4
And a flip-flop that operates with a command / data switching input / output command 20 as an input, 24 is a bus driver that receives the output of the flip-flop driver 22 and outputs the data 8 to the fluorescent display module 26, and 25 is the output of the flip-flop 23 The bus driver outputs the command / data switching signal 10 to the fluorescent display module 26 in response to the command.

FIG. 4 is a block diagram showing details of the fluorescent tube module 26. As shown in FIG. In the figure, reference numeral 13 designates the command / data 8 as a data / command write signal 21.
Based on this, a fluorescent display tube interface circuit for recording in the display RAM 15 has a scan control circuit 13A for controlling the anode driver 14 and the grid driver 17. Among them, anode driver 1
Numeral 4 scans the fluorescent display tube 16 as a display for each horizontal line, and the grid driver 17 drives each fluorescent display tube 16 in accordance with a control signal for turning on / off each dot.

In the data writing device for a display having such a configuration, the microprocessor 1 constituting the external control device receives CPU data 4 and a data output input / output command 19, command / data A switching input / output command 20 and a data / command write signal (WR) 21 are output. And CPU
The data 4 is latched by the data output input / output command 19 in the flip-flop driver 22 and further latched by the command / data switching input / output command 20 in the flip-flop 23. Further, the flip-flop driver 22 and the flip-flop 2
3 are input to bus drivers 24 and 25, and output data 8 and command / data switching signal 10
The fluorescent display tube is controlled and driven by the data / command write signal 21.

[0007]

However, in such a conventional data writing device for a display, when commands and display data for switching display screens and setting brightness are written from the microprocessor 1, After switching the command / data switching signal 10 for discriminating whether the data to be written is a command or display data, it is necessary to write the command and the display data to the fluorescent display tube 16. Therefore, the microprocessor 1
It becomes necessary to issue the command / data switching input / output command 20 and the data output input / output command 19, and as a result, issue the data output input / output command 19 and the command / data switching input / output command 20 once each. And the burden on the microprocessor 1 increases.

The present invention solves the above-mentioned problems, and a display which can easily and quickly write a command to a fluorescent display tube and display data by only issuing an input / output command signal once. It is an object of the present invention to obtain a data writing device.

[0009]

To achieve the above object,
According to a first aspect of the present invention, there is provided a data writing device for a display device, comprising: a command register and a display register for storing data sent from a microprocessor; and an address for display by decoding an address sent from the microprocessor. A decoder for generating an output command signal, and a command / data switching signal for selectively switching and storing data sent from the microprocessor in the command register or the display register with the display input / output command signal as an input. And a timing adjustment circuit for generating a write signal whose timing has been adjusted to the specifications of the display based on the display input / output command signal, based on the write signal. Write data from command register or display register It is obtained by Maseru way.

According to a second aspect of the present invention, in the data writing device for a display, the data is a command and display data to be written in the command register and the display register.

According to a third aspect of the present invention, there is provided the data writing device for a display, wherein the command / data switching signal generated by the flip-flop is used to display the lowest address from the microprocessor to the display input / output command signal. Is a signal obtained by latching the data.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a microprocessor which constitutes an external control device.
Is connected. Reference numeral 4 denotes CPU data output from the microprocessor 1, and reference numeral 5 denotes the lowest address (lowest address) of the addresses output from the microprocessor 1. Reference numeral 6 denotes a command register, which stores the display input / output command signal 3 and the lowest address 5 in each of the inverters 3.
The signals inversely converted at 1, 32 are further converted to NAND gates (N
AND) 33, based on the result of the logical AND operation,
The PU data 4 is stored.

Reference numeral 7 denotes a display register, which is based on a result obtained by performing an AND operation on a signal obtained by inversely converting the display input / output command signal by the inverter 31 and the lowest address 5 by a NAND gate (NAND) 34. , And CPU data 4. Reference numeral 8 denotes data including command and display data, and reference numeral 9 denotes a command / data switching signal (C / D) which latches the lowest address 5 in response to the display input / output command signal 3 and thereby outputs the command register 4 or the display register. 7 is a flip-flop for outputting the data 8 stored in 7.
A timing adjustment circuit 11 outputs a data / command write signal 12 adjusted to the specifications of a fluorescent display tube 16 as a display as shown in FIG. 4 based on a display input / output command signal. Upon receiving the write signal 12, it functions to write display data into the fluorescent display tube 16. Reference numeral 35 denotes an inverter that inversely converts the command / data switching signal and outputs an enable signal E1 for the command register 6. E2 is an enable signal for the display register 7.

Next, the operation will be described with reference to the timing chart of FIG. First, data (CPU data) 4 output from the microprocessor 1 is input to the command register 6 and the display register 7.
At this time, the CPU data is read in accordance with the display input / output command signal 3 obtained by decoding the address of the microprocessor 1 and the latch signals 27 and 28 of the NAND gates 33 and 34 to which the lowest address 5 is input. 4, the command is stored in the command register 6 and the display data is stored in the display register.

Subsequently, the lowest address 5 is latched by the flip-flop 9 with the display input / output command signal 3 and a command / data switching signal "0" or "1" is output, and these signals are commands. Alternatively, the display data is notified to the fluorescent display tube module 29.
Thereby, the command register 6 and the display register 7
And selectively outputs any of the command and the display data stored in the fluorescent display tube module 26. At this time, the command / display data is delayed by the command / data write signal 12 in which the display input / output command signal 3 is adjusted to the specifications of the fluorescent display tube 16 by the timing adjustment circuit 11, and the command and the display data are delayed. Write to. As described above, by issuing the display input / output command signal 3 once, the command and the display data can be written to the fluorescent display tube 16.
Therefore, when there are many commands and display data,
It is possible to avoid a decrease in the writing speed.

[0016]

As described above, according to the present invention, a display input / output command signal is input, and data transmitted from the microprocessor is selectively switched and stored in a command register or a display register. A flip-flop for generating a command / data switching signal is provided, and a timing adjustment circuit is caused to generate a write signal whose timing is adjusted to the specifications of the display based on the display input / output command signal, and based on the write signal. Since the display is configured to write data from a command register or a display register, it is possible to easily and quickly write a command to the fluorescent display tube and write display data only by issuing an input / output command signal once. The effect that it can be obtained is obtained. In addition, the data
Since the command and the display data are written to the command register and the display register, it is possible to obtain the effect that the command and the display data can be surely output using one output of the input / output command signal for display. Further, the command / data switching signal generated by the flip-flop is configured to be a signal obtained by latching the lowest address from the microprocessor by the display input / output command signal. The effect is obtained that data output switching can be performed alternately and reliably at the correct timing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a data writing device for a display according to an embodiment of the present invention.

FIG. 2 is a timing chart showing signals of respective parts of a block in the data writing device of the display device of FIG. 1;

FIG. 3 is a block diagram showing a conventional data writing device for a display.

FIG. 4 is a block diagram showing details of a fluorescent display tube module in FIG. 3;

5 is a timing chart showing signals of respective parts of a block in the data writing device of the display device of FIG. 3;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 microprocessor 2 decoder 6 command register 7 display register 9 flip-flop 11 timing adjustment circuit 16 fluorescent display tube (display)

Claims (3)

[Claims] 1. A command register and a display register for storing data sent from a microprocessor; a decoder for decoding an address sent from the microprocessor to generate a display input / output command signal; A flip-flop for generating a command / data switching signal for selectively switching data sent from the microprocessor to the command register or the display register and storing the data sent from the microprocessor with an input / output command signal for input; A timing adjustment circuit for generating a write signal whose timing is adjusted to the specifications of the display based on the output command signal and writing data from a command register or a display register to the display based on the write signal; Indicator data characterized by Writing device. 2. The data writing device according to claim 1, wherein the data is a command and display data written in the command register and the display register. 3. The command / data switching signal generated by the flip-flop is a signal obtained by latching a lowest address from the microprocessor by the display input / output command signal. Item 2. A data writing device for a display according to Item 1.