JPH10282932A - Portable equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transfer contents stored in resumption to a display RAM and to make it the same as display before suspension by transferring and storing a RAM for display of a liquid crystal screen directly before suspension to/in main RAM which can store and hold data during suspension at the time of suspension. SOLUTION: A CPU 5 reads a program from a ROM 7, and starts preparation for making a suspension state. Next, the CPU 5 transfers all contents of a RAM 3 for display to a region of a main RAM 6. Next, a CPU 3 stops supply from a power source 10 to a liquid crystal module 1 by controlling a power control signal and operating a switch device. Thereby, display of a liquid crystal screen 2 set to the liquid crystal module 1 is turned off, and contents of the RAM 3 for display are erased. After the CPU 5 makes a state in which contents are not erased even if the CPU 5 is in a suspension state for the main RAM 6, the CPU 3 itself is made a suspension state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a personal computer, a word processor, an electronic organizer, and a portable information terminal (P).
In particular, the present invention relates to an information device having a liquid crystal display device having a built-in display sequential read / write storage device, and to a circuit configuration for reducing the power consumption of the liquid crystal display device.

[0002]

2. Description of the Related Art The structure of a portable device with a built-in liquid crystal display device of a conventional sequential read / write storage device (hereinafter referred to as a RAM) will be described with reference to a circuit diagram of FIG.

Conventionally, this type of portable terminal has a liquid crystal display module 1 and a CPU 5 as shown in FIG.
, A main RAM 6, a ROM 7, a power supply 10, and a bus 9. Further, the liquid crystal display module 1 includes a liquid crystal screen 2, a display RAM 3, and a liquid crystal drive circuit 4.
It has the structure which has.

[0006] The liquid crystal screen 2 is connected to a liquid crystal drive circuit 4 and displays a screen by controlling the liquid crystal drive circuit 4. The liquid crystal drive circuit 4 is connected so that the contents of the display RAM 3 can be read, and by reading the contents, the contents to be displayed on the liquid crystal screen 2 can be known. It is connected via a bus 9 to execute instructions from the CPU 5.

The display RAM 3 comprises a CPU 5 and a main RA.
M6 is connected via a bus 9, and the contents of the display RAM 3 are stored in the main RAM 6 according to an instruction from the CPU 5.
Or the contents of the main RAM 6 can be written to the display RAM 3.

The liquid crystal display module 1 is obtained by integrating the liquid crystal screen 2, the display RAM 3, and the liquid crystal drive circuit 4 into one module.
The power is supplied to the liquid crystal screen 2, the display RAM 3, and the liquid crystal drive circuit 4 at the same time.

The power supply 10 includes a CPU 5 and a main RAM 6
And the same power as that supplied to the ROM 7, and when supplied to the liquid crystal display module 1, they are also supplied to them at the same time.

The CPU 5 processes the operation of the main body. The display RAM 3 and the liquid crystal driving circuit 4
And the main RAM 6 and the ROM 7. CPU
5 has a suspend / resume function.
The main body can shift to the suspend state before U5 itself enters the suspend state, and a series of operations can be performed so that the main body returns from the suspend state at the time of resume.

The ROM 7 stores the series of operations as a program, and the CPU 7
5 is connected.

Next, the operation of the prior art based on the above structure will be described. During normal operation, the power supplied from the power supply 10 supplies power to the liquid crystal display module 1, the CPU 5, the main RAM 6, and the ROM 7.

When the portable device shifts to the suspend state, the CPU 5 issues a command to the liquid crystal driving circuit 4 to turn off the display on the liquid crystal screen 2, and the liquid crystal driving circuit 4 turns off the display on the liquid crystal screen 2, and thereafter. The main RAM 6 is set to a state where the memory contents can be held (for example, in a self-refresh mode), the reading of the program from the ROM 7 is stopped, and the CPU 5 itself is in a suspend state.

At this time, in order to keep the contents of the display RAM 3, the power supply to the liquid crystal display module 1 must always be supplied. When resuming from the suspended state, the CPU 5 itself resumes, and thereafter, the CPU 5 reads the program from the ROM 7 and returns the main RAM 6 to a normal readable / writable state, whereby the main body completes the resume.

[0013]

In the prior art circuit,
There is a problem that the power supply to the liquid crystal display module cannot be turned off in order not to lose the data content of the display RAM during the suspend.

Further, in the prior art, there is a problem that power is consumed because the power of the liquid crystal display module cannot be turned off to hold the data in the display RAM at the time of suspending.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to turn off the power supply of the liquid crystal display module when the portable device is in a suspend state, and to reset the display RAM when the portable device is resumed. An object of the present invention is to provide a portable device capable of making data contents the same as contents immediately before suspend.

[0016]

In order to achieve the above object, the portable device of the present invention employs the following configuration.

In the portable device of the present invention, a liquid crystal screen, a display RAM for storing the contents of the liquid crystal screen, and a display R are provided.
A liquid crystal display module comprising the same power supply system having a built-in liquid crystal drive circuit for reading the contents of the AM and displaying the contents on the liquid crystal screen, a CPU capable of suspend / resume, and a main RAM capable of saving the contents of the display RAM ,
It is characterized by having a ROM in which a program executed by the CPU is stored, a power supply, and a switch device for turning on / off between the power supply and the liquid crystal display module by a power control signal output by the CPU.

[Operation] The features of the portable device of the present invention are as follows. A switch device for turning on / off the power supply to the liquid crystal display module, a main RAM for storing the display contents of the liquid crystal screen so that the contents of the display RAM can be erased, and a program for executing the same by the CPU. When the portable device enters a suspend state by turning on the power and turns off the power of the liquid crystal display module and resumes even if the contents of the display RAM are erased, the display contents of the liquid crystal screen are the same as the contents of the display RAM. Can behave as if they had been saved. In addition, by having this, the liquid crystal display module does not consume power during suspension.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments for implementing the portable device of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a circuit diagram showing a portable device according to an embodiment of the present invention.

First, the circuit structure of the present invention shown in FIG. 1 will be described. The liquid crystal screen 2 is connected to a liquid crystal drive circuit 4 and performs screen display under the control of the liquid crystal drive circuit 4. The liquid crystal drive circuit 4 is connected so that the contents of the display RAM 3 can be read, and by reading the contents, the contents to be displayed on the liquid crystal screen 2 can be known, thereby performing the display.

The display RAM 3 is also connected to the CPU 5 and the main RAM 6 via a bus 9.
According to a command from the PU 5, the contents of the display RAM 3 can be written to the main RAM 6, and conversely, the contents of the main RAM 6 can be written to the display RAM 3.

The liquid crystal screen 2, the display RAM 3, and the liquid crystal drive circuit 4 are combined into one module to form the liquid crystal display module 1, and the power supply 10 is connected to the liquid crystal display module 1
Is a device that can supply power to the liquid crystal display 2, the display RAM 3, and the liquid crystal drive circuit 4 at the same time.

A switch device 8 is provided between the power supply 10 and the liquid crystal display module 1. As the switch device 8, a relay or a field effect transistor (FET) can be applied.

When the switch device 8 is closed or opened, the power supply to the liquid crystal display module 1 can be turned on or off. On / off control of the switch device 8 can be performed by inputting a power control signal, and this signal is output from the CPU 5.

The power supplied to the CPU 5, the main RAM 6, and the ROM 7 is the same as the power supplied to the liquid crystal display module 1, but does not use a switch device. That is, even during the suspension, the supply is not lost, and is always supplied. As a result, the main RAM 6 does not lose its contents, and the contents are preserved even during the suspension.

The CPU 5 has a display RAM via the bus 9
3, the main RAM 6, and the ROM 7 are connected to each other, so that instructions for reading and writing between the display RAM 3 and the main RAM 6 can be executed according to the program in the ROM 7.

Next, the procedure performed by the CPU 5 in accordance with the program stored in the ROM 7 when the portable device shifts to the suspend mode will be described with reference to the flowchart of FIG.

The CPU 5 reads the program from the ROM 7 and starts preparations for bringing the system into a suspended state (FIG. 3A).

The CPU 5 transfers the entire contents of the display RAM 3 to the area of the main RAM 6 (FIG. 3B).

The CPU 5 controls the power control signal and turns off the power supply from the power supply 10 to the liquid crystal display module 1 by operating the switch device. As a result, the display on the liquid crystal screen 2 in the liquid crystal display module 1 is also turned off, and the contents of the display RAM 3 are also erased (FIG.
C).

The CPU 5 stores C in the main RAM 6
After the PU 5 is brought into a state in which the contents are not erased even in the suspend state (for example, a state like a self-refresh mode), the CPU 5 itself enters the suspend state (FIG. 3).
D).

The transition of the portable device to the suspended state is thus completed (FIG. 3-E).

Next, the procedure performed by the CPU 5 in accordance with the program stored in the ROM 7 when the main body resumes will be described with reference to the flowchart of FIG.

The CPU 5 receives an instruction to resume from a switch, for example, due to a certain factor, and starts the operation of resuming itself (FIG. 4F).

The resume of the CPU 5 itself is completed, and the operation for returning the liquid crystal display module to the original state is started (FIG. 4-G).

The CPU 5 controls the power control signal, and issues a command so that the switch device 8 supplies power to the liquid crystal display module. As a result, power is supplied from the power supply 10 to the liquid crystal display module 1, so that the display RAM 3 operates normally (FIG. 4H).

The CPU 5 returns the main RAM 6 from the suspended state to a state where normal reading and writing can be performed, and then transfers all the contents of the display RAM 3 saved in the main RAM 6 to the display RAM 3. As a result, the contents of the display RAM 3 become the same as the contents immediately before the suspend (FIG. 4-J).

The liquid crystal display module 1 includes a liquid crystal drive circuit 4
The contents of the display RAM 3 are displayed on the liquid crystal screen by the operation of. As described above, the resume operation ends, and the screen display becomes exactly the same as the screen display immediately before the suspend state.

[0039]

As is apparent from the above description, the portable device according to the present invention transfers the display RAM of the liquid crystal screen immediately before the suspension to the main RAM which can hold and store the data even during the suspension. By saving and saving and transferring the saved contents to the display RAM when resuming, the display can be made the same as the display before the suspension. Further, the power consumed by the LCD module at the time of suspending can be reduced to almost zero, and the power consumption can be further reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a liquid crystal display device driving device of a portable device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a liquid crystal display device driving device of a portable device according to the related art.

FIG. 3 is a flowchart illustrating suspend control of the mobile device according to the embodiment of the present invention.

FIG. 4 is a flowchart illustrating resume control of the mobile device according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display module 2 Liquid crystal screen 3 Display RAM 4 Liquid crystal drive circuit 5 CPU 6 Main RAM 7 ROM 8 Switch circuit 9 Bus 10 Power supply

Claims (2)

[Claims] 1. A liquid crystal display device including a display sequential read / write storage device, a liquid crystal display capable of displaying the contents of the display sequential read / write storage device, and a liquid crystal drive circuit, and a suspend for controlling a system of the main body. A CPU capable of resume operation, and a sequential read / write memory used as a storage area for storing the contents of a display sequential read / write storage device in addition to the contents of the main body at the time of suspending, which is used for controlling the main body during normal operation ROM that stores the software that controls the device and the main unit
A bus connecting the CPU, the display sequential read / write storage device, the sequential read / write storage device and the ROM, a power supply for supplying the liquid crystal display device, and turning on / off a supply from the power supply to the liquid crystal display device. A portable device comprising a switch device. 2. The portable device according to claim 1, wherein the switch device uses a relay or a field effect transistor.