JPH04245295A - Electronic apparatus - Google Patents

Abstract

PURPOSE:To reduce the power consumption by resting the reading of the display data from a VRAM when no data is inputted from an input means for a fixed period in an electronic apparatus using a display device holding the display data for individual picture elements. CONSTITUTION:An electronic apparatus is constituted of an input means 1, a memory means 5 storing display data, a control means 6 reading the display data from the memory means 5, a display device 7 holding the display data read by the control means 6 for individual picture elements and displaying the display data, and a means resting the reading of the display data read by the control means 6 when it detects that no data is inputted from the input means 1 continuously for a fixed period. The power consumption of the portable electronic apparatus can be reduced.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

[Industrial Application Field] The present invention is applicable to, for example, TFT (Th
in Film Transistor) active matrix liquid crystal display (hereinafter referred to as TFTL)
The present invention relates to electronic equipment using a display device such as a CD (CD) that holds display data for each pixel.

0002

2. Description of the Related Art Currently, electronic devices such as personal computers are becoming smaller and lighter so that they can be easily carried and used anywhere. Furthermore, in order to enable long-term use on battery power, small, lightweight batteries with large power capacities have been developed, and efforts have been made to reduce the power consumption of electronic devices.

[0003] For example, automatic sleep mode is one of the ideas for power saving. This automatically puts the system into a hibernation state if there is no keyboard input for a certain period of time, and then returns the system to normal operation if there is any keyboard input.

Conventionally, CRT, plasma display, S
In the screen display of electronic equipment equipped with a display device such as a TN-type LCD, reading display data from VRAM, outputting display data to the display device, and displaying the screen on the display device are performed without changing the screen display contents. Regardless, it was done periodically. This is because when such a display device is used, the screen display disappears unless display data is sent periodically. By the way, TFT
Regarding electronic equipment equipped with display devices such as LCDs that have the function of storing display data for each pixel,
Similarly, display data is periodically read out from the VRAM, the display data is output to a display device, and the screen is displayed on the display device.

[0005]

[Problem to be solved by the invention] Originally, TFT LC
Since D has a function of storing display data for each pixel, there should be no need to read out display data from the VRAM when the same screen display continues. A situation where the same screen display continues occurs quite frequently. for example,
When using word processing software with a Persol computer, you may not change the screen display when you are thinking about a sentence in front of the display screen or when performing complex calculations.

[0006] However, in conventional systems, the VRAM, display control circuit, and display device are constantly operating for screen display, making it impossible to reduce power consumption for screen display operations.

The present invention has been made in view of the above points, and when a state in which no data is input continues for a certain period of time, the reading of display data from the VRAM is stopped, thereby stopping the display data from the VRAM. An object of the present invention is to provide an electronic device that reduces power consumption required for reading data and writing data to a display device. [Structure of the invention]

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an electronic device including an input means for inputting data, and a memory for storing display data corresponding to the data input from the input means. means, a control means for reading display data from the storage means, a display device for holding the display data read by the control means for each pixel and displaying the display data, and a display device for inputting data by the input means. and means for suspending reading of display data by the control means when the detection means detects that no data has been input for a certain period of time. be.

[0009]

[Operation] According to the present invention, the input means inputs new data. The storage means holds display data corresponding to data input from the input means. The control means reads display data from the storage means. The display device is constituted by a group of pixels having a function of holding display data read out by the control means, and displays the display data sent from the storage means on the screen. The detection means detects that there is no input for a certain period of time by the display data input means. When the detection means detects that there is no data input for a certain period of time, reading of display data by the control means is suspended. Accordingly, the display data is read from the storage means only when the display data is rewritten by the input means, so power consumption can be reduced.

0010

[Examples] Examples of the present invention are shown below.

FIG. 1 is a system configuration diagram of an electronic device according to an embodiment of the present invention. A keyboard 1 is a means by which a user inputs data. The KBC 2 is a keyboard controller and has a function of notifying the interrupt controller 9 when data is input from the keyboard 1. The interrupt controller 9 has a function of interrupting the CPU 4 upon receiving a notification from the KBC 2. Bus 3 is C
This is a signal line that connects the PU 4, KBC 2, VRAM 5, display control circuit 6, main memory 8, and timer 10, and transmits address/data/control information between each device. CPU4 controls the entire system, and VRAM5
Writes display data to the memory, controls the timer 10, etc. The main memory 8 stores programs for operating the CPU 4, data, and the like. VRAM5 is Vid
eoRAM is a memory that stores display data. The display control circuit 6 has a function of receiving a write command from the CPU 4 to the VRAM and writing display data to the VRAM, and a function of reading data to be displayed from the VRAM 5 and sending it to the display device 7. The display device 7 is, for example, TFT L.
It has the function of holding display data for each pixel like a CD, and visually displays the display data. The timer 10 counts time based on a control signal from the CPU 4. The CPU 4 resets the timer 10 every time it receives an interrupt indicating an input from the keyboard 1. After counting a certain period of time, the timer 10 notifies the CPU 4 of the completion of counting. Next, the operation of the system associated with changing the display contents according to this embodiment will be described in detail.

The user inputs keys using the keyboard 1. The input key is converted into key code data by the KBC 2 and temporarily held, and the interrupt controller 9 is notified of the key input. The interrupt controller 9 receives this notification and sends an interrupt command to the CPU 4. When the CPU 4 receives an interrupt instruction, it reads the key code data from the KBC 2. CPU 4 receives the key code data and converts it into a character pattern.
Write to AM5. The display control circuit 6 displays VR at predetermined intervals.
The display data of AM5 is read and the data is sent to the display device 7. Further, when the CPU 4 receives an interrupt command from the interrupt controller, it sends a reset signal to the timer 10. When the timer 10 receives this reset signal, it clears the counter and starts counting time again.

Here, the timer 10 sends a count completion signal to the CPU 4 after counting for a certain period of time. CPU
4 receives this signal and sends the VRAM 5 to the display control circuit 6.
Sends a control signal to pause reading of display data. The display control circuit 6 suspends reading from the VRAM 5 based on this control signal. This reduces power consumption because the display data is sent to the display device 7 only when there is a change in the display data.

[0014]

[Effects of the Invention] As described in detail above, the present invention enables electronic equipment to read display data from VRAM by not reading display data from VRAM when display data is not input for a certain period of time. In addition, power consumption required for writing data to a display device can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram showing the overall configuration of an electronic device according to an embodiment.

[Explanation of symbols]

1 Keyboard 2 KBC 3 Bus 4 CPU 5 VRAM 6 Display control device 7 Display device 8 Main memory 9 Interrupt controller 10 Timer

Claims (1)

[Claims] 1. An input means for inputting data, a storage means for storing display data corresponding to data input from the input means, a control means for reading display data from the storage means, and a control means comprising: a display device that holds read display data for each pixel and displays the display data; a detection device that detects that a state in which no data is inputted by the input device continues for a certain period of time; An electronic device comprising means for suspending reading of display data by the control means when it is detected that no data has been input for a certain period of time.