JPH09258704A - Lcd display control circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manage without changing a CUP in the case of changing a dot matrix LCD to a seven-segment LCD so as not to generate the change of wiring on the CPU and the design change of software or the like. SOLUTION: A CPU 1 outputting a display signal for a dot matrix LCD normally uses a dot matrix LCD 5, so that it is connected as shown by a dotted line, but in the case of changing design so as to use a sevensegment LCD 3, the CPU 1 is connected to an LCD display control circuit 2 as shown by a continuous line. The LCD display control circuit 2 is composed of an LCD display signal converting part 21 for converting a dot matrix display signal into a seven-segment display signal by software processing, and a seven-segment LCD control part 22, an LCD driver.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LCD display control circuit, and more particularly to an LCD display control circuit for driving a dot matrix LCD or a 7-segment LCD with an LCD display signal output from a CPU.

[0002]

2. Description of the Related Art Conventionally, this type of LCD display control circuit is
It is a driver that is provided between the CPU and the LCD used to convert the display signal output from the CPU into an LCD drive signal. LCDs include dot matrix LCDs and 7-segment LCDs, and display that interfaces with the CPU. The signals and the drive signals that interface with the LCD are also different for this LCD. Therefore, LCD display control circuit is for dot matrix LCD and for 7 segment L
Different dedicated ones are used for CDs.

For example, when looking at an LCD display control circuit in a mobile phone or the like, when the overall control unit (CPU) of the device (mobile phone or the like) is a single-chip microcomputer, the device is developed in various models. For,
When the LCD used changes each time, the CPU and LC
The D display control circuit is selected and used according to the LCD to be used.

[0004]

As described above, in the conventional LCD display control circuit, since the interface with the CPU is changed according to the LCD used, the LCD used is, for example, from the dot matrix type to the 7-segment type. If the LCD display control circuit is changed to CP,
Since U is also changed, the wiring of the CPU side board is changed, the software of the CPU relating to display control is changed, and the design change is troublesome.

[0005]

An LCD display control circuit according to the present invention inputs a dot matrix LCD display signal from a CPU controlling each part of the device, converts it into a 7-segment LCD display signal by software processing, and outputs it. And an LCD control unit for inputting the 7-segment display signal and outputting a drive signal for driving the 7-segment LCD.

In particular, the LCD display signal conversion section includes the C
A receiving unit for receiving the dot matrix LCD display signal from the PU, a translation unit for converting the dot matrix LCD display signal command system into a 7-segment LCD display signal command system by software processing, and the translated unit. And a communication unit for sending a display signal for the dot matrix LCD to the LCD control unit.

[0007]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a time chart showing the conversion process of the display signal in FIG.

In FIG. 1, a CPU 1 controls each part of the apparatus and outputs a display signal for a dot matrix LCD to display a control result and the like. Dot matrix L
When the CD 5 is used, it can directly interface with the CPU 1 and is directly connected to the dot matrix LCD control unit 4 having an LCD driver function as shown by a dotted line.
When the 7-segment LCD 3 is used for the CPU 1, the LCD display control circuit 2 of the present invention is connected as shown by the solid line.

The LCD display control circuit 2 receives the dot matrix LCD display signal from the CPU 1, converts the dot matrix LCD display signal into a 7-segment LCD display signal by software processing, and outputs it. Input 7-segment display signal, 7-segment LC
LCD control unit 22 that outputs a drive signal for driving D
And

FIG. 2 shows a time chart for explaining the operation of the LCD display control circuit 2. In this figure, as an example of the case where a character is blinkingly displayed at the address 00 of the LCD display virtual area, as a software chart inside the CPU 1, first, a display operation request is issued and at the same time,
As parameters P1: instruction code (blink), P
The three factors of 2: logical address (00) and P3: character code (value other than 0) are passed to the translation unit. Upon receiving this, the translation unit causes the communication unit to transmit the translated physical address and then the character code. This physical address and character code instruction system is for a dot matrix LCD.

The LCD display signal converter 21 of the LCD display control circuit 2 receives the physical address and then the character code. The data received by the receiver is passed to the translator. The translation unit translates the received reception data into a command system for a 7-segment LCD, and transmits the translated physical address and character code to the communication unit.

The 7-segment LCD control unit 22 receives the physical address and then the character code to turn on the character of the physical address corresponding to the logical address 00 of the 7-segment LCD. The translation unit of the CPU 1 monitors the blink time, and when the blink half cycle has passed, the translated physical address and this time a clear code (for example, a space character) are transmitted, and the physical address corresponding to the logical address 00 is sent. Is turned off. After that, the blink display is performed by performing the above-described processing every half-cycle of blinking.

[0013]

As described above, the LCD display control circuit of the present invention can convert the display signal for the dot matrix LCD into the drive signal for the 7-segment LCD, so that the display signal for the dot matrix LCD is converted. A 7-segment LCD can be used even for the CPU that outputs. Therefore, since it is not necessary to change the CPU even if the LCD is changed, it is not necessary to change the wiring of the board related to the CPU or the software, and the effect of reducing the design change can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration in an exemplary embodiment of the present invention.

FIG. 2 is a time chart explaining the operation in FIG.

[Explanation of symbols]

 1 CPU 2 LCD display control circuit 3 7-segment LCD 4 Dot matrix LCD control unit 5 Dot matrix LCD 21 LCD display signal conversion unit 22 7-segment LCD control unit

Claims (2)

[Claims] 1. An LCD display signal conversion unit for inputting a dot matrix LCD display signal from a CPU controlling each unit of the device, converting the dot matrix LCD display signal into a 7 segment LCD display signal by software processing, and outputting the 7 segment LCD display signal. An LCD display control circuit, comprising: an LCD control unit for inputting a signal and outputting a drive signal for driving a 7-segment LCD. 2. The LCD display signal converter is configured to control the CP.
A receiving unit for receiving a dot matrix LCD display signal from U, a translation unit for converting the dot matrix LCD display signal command system into a 7-segment LCD display signal command system by software processing, The 7-segment LCD display control circuit according to claim 1, further comprising a communication unit that sends a dot matrix LCD display signal to the LCD control unit.