Portable electronic device

Abstract: A portable electronic device comprises a control section comprising CPU (22) and ROM (14) which turn off a power (21) if a keyboard (13) has not been operated for a predetermined period of time, set whether the power is to be turned off, and set the predetermined period of time in which the power is turned off. The ROM (14) saves data which is being processed when the power is turned off, even after the power is turned off. The CPU (22) enables the process which is interrupted when the power is turned off to be resumed, on the basis of the data stored in the ROM (14) and determines whether to resume the process which is interrupted when the power is turned off.

Description: This invention relates to a portable electronic device such as a handy terminal, and more particularly to a portable electronic device which has means for automatically turning off a power source upon lapse of a predetermined time from the last keyboard operation, and which performs a resume function of maintaining data in a program memory which has been processed until the power source is turned off, and then enabling a user to resume the processing of the data when the power source is turned on by the user. In recent years, portable electronic devices which are driven by batteries have been developed, and utilized in the fields of distribution, finance, traffic, and the like. The battery used in these devices must be small and light since the devices would otherwise be larger and heavier. The smaller the battery, the less the power storage. To operate the battery-driven devices as long as possible, the devices must have means for saving power. This is why hand-held calculators, for example, have automatic power-off means. Without automatic power-off means, a device will waste power if the user forgets to turn off the power switch or turns on the power switch unnecessarily. To save power, the user may turn off the power switch upon finishing a data processing. Every time he or she turns off the switch, the data is erased and can no longer be processed. Prior art document EDN ELECTRICAL DESIGN NEWS, vol. 28, no. 8, 1 April 1983, NEWTON, MASSACHUSETTS, US; pages 123 - 131; R. C. CUSHMAN: "Hands-on investigations help exploit CMOS designs", discloses a portable electronic device comprising: a CPU board for executing a data processing, a digital I/O board and a "LCD" for displaying data, and a power supply board for the LCD. Further, prior art document HEWLETT-PACKARD JOURNAL, vol. 37, no. 7, 1 July 1986, PALO ALTO US, pages 4 - 13; J. T. EATON ET AL.: "Design of HP's portable Computer family", discloses a portable computer comprising a means for turning off the power the computer when it is not used; when doing so, a display means is also turned off, and a processing state is saved before the power is turned off. This computer also comprises first setting means for setting whether to effect an automatic power-off function for automatically ceasing the power supply for data processing when a predetermined period of time has passed after an input operation for the data processing, second setting means for setting whether to effect a resume function for performing data processing succeeding to the data processing which is being performed when the power supply is ceased, and means for automatically ceasing the power supply according to the first setting means if setting the automatic power-off by function the first setting means is effective. It is an object of the present invention to provide a compact and light portable electronic device, which can determine whether an automatic power-off function is to be performed, whether a resume function is to be performed, or whether an operation is to be resumed when the power source is turned on after the power source has been turned off, thereby saving power without erasing necessary data. To solve this object the present invention provides a portable electronic device as specified in claim 1. This invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: Fig. 1A is a top view showing a portable electronic device according to an embodiment of the present invention; Fig. 1B is a left-side view of the device; Fig. 1C is a front view of the device; Fig. 1D is a right-side view of the device; Fig. 1E is a back view of the device; Fig. 1F is a bottom view of the device; Fig. 2 is a block diagram showing the control section of the device shown in Fig. 1; Fig. 3 is a flowchart explaining operations of the device shown in Fig. 1 to turn off the power source; Fig. 4 is a flowchart explaining operations of the device shown in Fig. 1 to turn on the power source; Figs. 5A and 5B are views showing some examples of coding for setting the automatic power-off and resume function modes of the device shown in Fig. 1; and Fig. 6 is a view showing the message displayed when the resume function is selected. Figs. 1A to 1F show in different directions a portable electronic device according to an embodiment of the invention. The device has, on its back side, interface connector 11 for down-loading of an application program from an external device and for achieving data communication, so that an application program can be replaced with another through communication means. The device also has, on its front side, liquid crystal display (LCD) 12 and keyboard input section 13, so that the device can operate without an external device. Keyboard input section 13 includes a power key, operation keys, and the like. The device contains control section 10 shown in Fig. 2 for controlling operations of the device. Control section 10 comprises central processing unit (CPU) 22, read only memory (ROM) 14, keyboard interface 17, LCD controller 18, communication interface 15, clock generator 19, and interruption controller 20, all of which are connected to one another via a bus line. The bus line is connected to power source or battery 21 by a switch which is opened or closed by operating the power key. ROM 14 stores an operating system for controlling the entire control section. Application program 23 developed in an external personal computer or the like is down loaded to random access memory (RAM) 16 via connector 11 and communication interface 15. RAM 16 is either of a battery back-up type or a nonvolatile type, so that data stored in RAM 16 is not erased even after power source 21 has been turned off. Keyboard 13 is connected to keyboard controller 17. LCD 12 is connected to LCD controller 18. Clock generator 19 decrements the count of the counter incorporated in CPU 22, whereby CPU 22 causes the power source to be automatically turned off upon lapse of a predetermined period of time. The operation of the above-described device will now be described with reference to Figs. 3 and 4, assuming that an external application program includes a system determining whether the power source is automatically turn off, how long the limit period is in which the power source can be kept on after the last keyboard operation, and whether the resume function is selected. In the flowchart of Fig. 3 representing steps for turning off the power source, in a state of waiting for key input (ST1), the counter is set to a value corresponding to the limit period set in the application program for automatically turning off the power source (ST2). Then, keyboard scanning is performed by ordinary key operations (ST3). During the key operations, CPU 22 determines whether operations are continuously performed (ST4). If YES in step ST4, unless the power key is turned off or an OFF key is depressed (ST5), processes are executed based on the key input data (ST6). When the key input is determined to cease in step ST5, the counter decrement starts (ST7). Then, CPU determines whether the counter value decreased to 0 (ST8). If the counter value is 0, i.e., if the limit period has been elapsed, CPU determines that the resume function is selected (ST9). If the key operation is restarted before the counter value reaches 0, the flow returns to the step ST3. If it is determined that the resume function is to be effected, a resume flag is set (ST10), and all of the register values, flag values, and parameters are saved (ST11). Thereafter, the power is turned off (ST12). If it is determined that the resume function is not selected in step ST9, the power is turned off, without executing steps ST10 and ST11. If the OFF key is depressed in step ST5, the flow advances directly to step ST9 in which the resume function is determined to be effected, since the automatic power-off function is unneeded. It will now be described with reference to Fig. 4 how the device operates when the power key is depressed after the automatic power-off. When the power source is turned on by operating the power key (ST13), it is determined whether the resume function is effective (ST14). If YES, LCD 12 displays a message for determining whether a resume operation is to be performed (ST15). In determining whether a resume operation is to be performed (ST16), if the keyboard is operated to give an instruction for performing a resume operation (i.e., the return key is depressed), the flags and parameters, which have been saved since the power was turned off, are loaded (ST17) and the application program is run (ST18). Thus, the operation which has been interrupted when the power source was turned off can be resumed. On the other hand, if the resume function is determined to be ineffective in step ST14, or if the keyboard is operated to give an instruction for not performing a resume operation (i.e., a key other than the return key is depressed) in step ST16, the application program in RAM 16 is activated (ST19). The application program including the coding as shown in Fig. 5A will be described below. A command "auto-off (i)" is for setting a limit period for the automatic power-off function. With this command, an instruction to turn off the power source in i seconds is sent to RAM 16. When i=0, the command instructs that the power source 21 should not be turned off. Commands "resume-on( )" and "resume-off( )" are respectively for validating and not invalidating the resume function. The coding as shown in Fig. 5A achieves the functions as shown in Fig. 5B. In the states (3) and (4) shown in Fig. 5A, i.e., when both the automatic power-off function and the resume functions are effective, if no operation is performed within the set periods, power source 21 is turned off. At this time, the statuses of all flags and the values in all resistors are stored in RAM 16. The power-off means a state in which at least display of LCD 12 is turned off and no keys of keyboard input section 13 except the power key have been operated. It would be well understood that the operations shown in Figs. 3 and 4 are performed by CPU 22 in association with the other components. When power source 21 is turned on by operating the power key, LCD 12 represents instructions to depress the return key if the interrupted program is to be resumed, and to depress any other key if the program is not to be resumed, as shown in Fig. 6. If the return key is depressed, the application program is resumed. If any other key is depressed, the interrupted program is not resumed, in which case the flags and resistors are reset and the application program is activated. As described above, the application program contains an operating system to determine whether the automatic power-off function is set, how long the limit time is, and whether the resume function is set, or an operating system to select whether a resume operation is performed when the power is turned on after the automatic power-off. The above control is executed by the operating system on ROM 14. The above-mentioned application program can either be supplied from an external device such as a main computer, or by a memory medium removably connected to the present device. As has been described above, the present invention can provide a compact and light portable electronic device, which can determine whether an automatic power-off function is to be effected or not, and in which the limit period of time for turning off the power can be set to a desired value, and power can be saved without erasing necessary data.

Claims: A portable electronic device comprising: control means (10) for executing a data processing; display means (12) for displaying data; and a power source means (21) for the display means; said control means (10) comprising: first means (14, 22) for turning off the power to the display means; and second means (14) for saving a processing state before the first means turn off the power; characterized in that the control means (11) further includes: third means (13, 14, 22) for determining whether to resume, a process from the processing state which is saved by the second means or not when the power is turned on; and fourth means (12, 14, 22) for resuming the process on the basis of the data saved by the second means when the third means is selected to resume the process. A device according to claim 1, characterized in that said second, third and fourth means include a RAM (14), and means (22) for causing the RAM (14) to store data for setting whether to turn off the power, data for setting the predetermined period of time, and data for enabling the process which is being processed when the power is turned off to be resumed. A device according to claim 2, characterized by further comprising means (11, 15) for electrically and exchangeably connecting said second means (14) for causing the RAM to store data to a main body. A device according to any one of claims 1 to 3, characterized in that said third means (13, 14, 22) include means (14, 22) for causing the display means (12) to indicate the resume function is to work or not, and means for selecting fulfilling or not the resume function based on the indicate by the display. A device according to any one of claims 1 to 4, characterized by further comprising: fifth means (14, 22) for setting the first means (14, 22) whether to turn off the power; and sixth means (12, 14, 22) for setting the predetermined period of time in which the power is turned off by the first means (14, 22). A portable electronic device according to any one of claims 1 to 5, characterized by further comprising: seventh means (13) for selecting fulfilling or not the resume function. A device according to any one of claims 1 to 6, characterized in that said first means (14, 22) include means for setting a desired period of time for the automatic power-off function. A device according to claim 7, characterized in that said first means (14, 22) include a storage means (14) for storing the set time. A device according to claim 6, characterized by further comprising guidance display means for inputting whether to fulfill the resume function or not. A portable electronic device according to any one of claims 1 to 9, characterized by further comprising: eigth means (12, 14, 22) for returning to a processing state, when said fourth means instructs to return to said processing state. A device according to claim 9, characterized in that said fourth means comprise guidance means for instructing said display means (12) to display a guidance message for inputting an instruction whether to return to said processing state, and input means for inputting an instruction whether to return to said processing state with reference to the guidance message. A device according to claim 9, characterized by further comprising means (12, 14, 22) for instructing to return to an initial state, when the fourth means instruct not to return to said processing state.

Inventors: FUJIMORI ATSUSHI, FUJIMORI, ATSUSHI, FUJIMORI, ATSUSHI, C/O INTELLECTUAL PROPERTY DIV.
Applicants: TOSHIBA KK, KABUSHIKI KAISHA TOSHIBA
Application year: 1990
Main classification: G06F1
IPC codes: G06F15, G11C7, G06F11, G06F1