JP2007018428A - Personal digital assistance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a personal digital assistance for detecting a state, where it is highly possible that an operation source voltage is lowered, to surely maintain storage contents in a volatile memory. <P>SOLUTION: When a battery cover detection switch 19 detects that a battery cover has been opened, a microcomputer 4 in the portable digital assistance 1 transfers information of a file management area among contents stored in an SDRAM 5 to an FROM 6, powers off a main body, when completing the transfer, switches the operation power source from a battery 2 to a sub-battery 12, and continues backup for the SDRAM 5 for a prescribed time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a portable information terminal including a battery for supplying power for operation and a volatile memory in which data is rewritten relatively frequently during normal operation.

Patent Document 1 discloses the following configuration. That is, when the power of the battery pack 2 that has been attached is gradually consumed with the operation of the mobile terminal 10 and the remaining battery level is below a certain value, the battery pack is in a state that needs to be charged or replaced on the display. A message to that effect is displayed. When the user removes the battery pack 2 from the portable terminal 10, the detector 4 detects the state (abrupt voltage level drop) and outputs a detection signal to the selector 5. Then, the power supplied to the selector 5, the CPU 1, and the volatile memory 6 is switched from the battery pack 2 to the backup battery 3 side.
JP 2003-101624 A

In the technique disclosed in Patent Document 1, when the battery pack 2 is actually removed from the portable terminal 10 and the detection voltage level by the detector 4 becomes “zero”, the switching to the backup battery 3 is performed. Yes. In addition, the timing of transferring the storage contents of the volatile memory 6 to the nonvolatile memory 7 is performed when a certain time has passed after the volatile memory 6 is shifted to the state of being backed up by the backup battery 3. (See paragraph (0019)).
However, in the above technique, the storage content of the volatile memory 6 is transferred to the non-volatile memory 7 using the backup battery 3 as a supply power source. There is a risk of disappearing.

  The present invention has been made in view of the above circumstances, and its purpose is to detect in advance a state that is highly likely to cause a decrease in the operating power supply voltage, and to maintain the stored contents of the volatile memory. The object is to provide a portable information terminal that can be more reliably achieved.

According to the portable information terminal of the first aspect, when the battery cover open detecting means detects that the battery cover of the main body is opened, the control means at least the file management area of the stored contents of the volatile memory. Transfer information to non-volatile memory. When the transfer is completed, the main body is turned off, the operation power supply is switched from the battery to the backup power supply, and the backup to the volatile memory is continued for a predetermined time.
That is, for example, when the user intentionally opens the battery cover of the main body, it is assumed that the battery is subsequently removed from the storage unit. In addition, for example, even when the battery lid is opened due to an external force applied to the portable information terminal, it is assumed that the battery subsequently drops due to the impact. Therefore, when the above event is detected, first, at least information in the file management area is transferred from the volatile memory to the nonvolatile memory, and information necessary for managing the data file in the nonvolatile memory is lost. By reliably avoiding the above, the storage contents of the volatile memory can be more reliably maintained. In addition, since the data transfer is performed while the operation power is supplied from the battery, the transfer can be reliably completed while the power is stable.

  Then, after the transfer is completed, the main body is turned off, the operation power supply is switched to the backup power supply, and the backup to the volatile memory is continued for a predetermined time. That is, since it is assumed that the user powers on the terminal again after the portable information terminal is powered off, if the backup of the volatile memory is continued, the data held in the volatile memory Can be read immediately, and the operating state before powering off can be immediately restored.

  According to the portable information terminal of the second aspect, the other device that is backed up by the backup power source can operate up to a voltage that is smaller than that of the volatile memory and lower than that of the volatile memory. In some cases, the control means stops the backup to the volatile memory when the backup power supply voltage falls below the lower limit value. With this configuration, it is possible to secure a longer time for backing up the storage contents of other devices.

  According to the portable information terminal of the third aspect, the device is a real-time clock IC that performs timekeeping. That is, it is desirable that the real-time clock IC retains the set data as much as possible in order to continue the time measurement based on the date and time data once set. Therefore, the present invention can be effectively applied to a portable information terminal including a real time clock IC.

According to the portable information terminal of the fourth aspect, when the power-off key of the main body is pressed in a state where the battery is stored in the storage unit, the control means, on the volatile memory, as in the case of the first aspect. At least the information of the file management area is transferred to the nonvolatile memory, and after the transfer is completed, the main body is set in the sleep state. After that, when a predetermined time elapses, the sleep state of the main body is canceled, the work area information is transferred to the nonvolatile memory, and then the backup to the volatile memory is stopped to put the main body in the power-off state.
In other words, even if the main unit is powered off by the user's intention, it may be powered on again, so the file management area information on the volatile memory is transferred to the non-volatile memory and then the main unit is put to sleep. Put it in a state. Therefore, the information on the memory can be quickly read within a predetermined time during which the volatile memory is backed up. Further, since the data transfer in this case is also performed while the operation power is supplied from the battery, the transfer can be completed with certainty.

  After that, when a predetermined time has elapsed, after placing importance on ensuring that the work area information on the volatile memory is backed up, canceling the sleep state of the main unit, and transferring the information to the non-volatile memory Stop backup to volatile memory. Therefore, when volatile memory is also used as a work area, information in the file management area is preferentially saved, and information on the work area is also stored when there is a high possibility that backup to the volatile memory cannot be maintained. By evacuating, information can be backed up step by step according to importance.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows only an electric configuration of a portable information terminal such as a barcode handy terminal according to the gist of the present invention. The portable information terminal 1 has a configuration in which, for example, a power source of a lithium ion battery 2 having a voltage of 3.0 V to 4.2 V is driven by a 3 V operation power source (main power source) stabilized via a power source circuit 3. is there.
The main power is supplied to a microcomputer (control means) 4, SDRAM (volatile memory) 5, flash ROM (FROM, nonvolatile memory) 6, voltage detection circuit 7, real-time clock IC (RTC) 8, and the like ( However, it is supplied to the SDRAM via the Schottky diode 9). The voltage of the main power supply is monitored by the voltage monitoring circuit 10, and when the voltage drops to a predetermined level (low battery), the voltage monitoring circuit 10 sends a low battery detection signal to the microcomputer 4. It is designed to output.

Further, the power supply of the battery 2 is boosted to 5 V via the DC / DC converter 11 and supplied to the sub-battery (backup power supply) 12 and the linear regulator 13 which are composed of, for example, an electric double layer capacitor having a capacity of about 1.5 F. Has been. The linear regulator 13 generates a voltage of 3.1 V from the 5 V voltage, and supplies a backup power supply (BU3V) to the voltage detection circuit 7 and the RTC 8 via the Schottky diode 14. The backup power is also supplied to the SDRAM 5 via the P-channel MOSFET 15.
The RTC (device) 8 is configured such that the set time data and the like are backed up by a backup power source, but the current consumption at the time of backup is about 10 μA. On the other hand, the current required for backup while refreshing the data in the SDRAM 5 is about 800 μA. The lower limit of the operable voltage of the SDRAM 5 is 2.7 V, and the lower limit of the operable voltage of the RTC 8 is further lower than 2.7 V (for example, about 1.5 V).

The gate of the FET 15 is connected to the source of the resistor 16 and the Q bar output terminal of the D flip-flop 17. The flip-flop 17 is set / reset by inputting data and a clock from the microcomputer 4. The Q output terminal of the flip-flop 17 is connected to the input port of the microcomputer 4 via the diode 18 in the reverse direction. Note that the anode side of the diode 18 is pulled up to the main power supply, and the diode 18 allows current to flow into the input port of the microcomputer 4 when the supply of the main power supply is stopped and only the backup power supply is active. Arranged to prevent.
A detection output signal of the voltage detection circuit 7 is given to a clear terminal (negative logic) of the flip-flop 17. The voltage detection circuit 7 monitors the backup power supply voltage when the supply of the main power supply is stopped, and when the input voltage decreases from (3.1-0.3 =) 2.8V to 2.7V, The detection output signal is changed to a low level. The signal output terminal is pulled up to a backup power source. At that time, since the flip-flop 17 is cleared, the FET 15 is turned off.

  Further, the case of the portable information terminal 1 has a battery cover (none of which is shown) that is opened and closed when the battery 2 is housed and taken out from the case, and the microcomputer 4 is in an open / closed state of the battery cover. Can be recognized by turning on / off the detection switch (battery cover open detection means) 19. The microcomputer 4 can communicate with an external host 21 via a communication interface (I / F) 20, and a data file downloaded from the host 21 is written in the FROM 6. .

  The output signal of the power switch 23 for the user to switch the power on and off of the main body of the portable information terminal 1 is supplied to the power supply circuit 3 through the three-input OR gate 24 and also to the input port of the microcomputer 4. It has been. The remaining two input terminals of the OR gate 24 are connected to the output port of the microcomputer 4 and the output terminal of the RTC 8, respectively. When the microcomputer 4 is activated after the power switch 23 is pressed, the microcomputer 4 outputs a high level to the OR gate 24 and maintains the power-on state. When the main power supply is stopped and the power is turned off, the microcomputer 4 outputs a low level. The RTC 8 controls the power supply circuit 3 in order to realize the timer activation of the portable information terminal 1 and the like.

  Next, the operation of the present embodiment will be described with reference to FIGS. In FIG. 3, the mobile information terminal 1 is shifted from an initial power-off state (a) to a power-on (b), a data file download (c), and a power-off process (d). The memory image of FROM6 and SDRAM5 in the meantime is shown.

In the initial state shown in FIG. 3A, the FROM 6 has a control program area in which a control program is stored and a data area in which other data files are stored. The file management area includes these areas. Information for managing the data file is stored. When the portable information terminal 1 is powered on as shown in FIG. 3B, the file management area of the FROM 6 is transferred to the SDRAM 5. When the microcomputer 4 starts operation, part of the SDRAM 5 is used as a work area.
Further, as shown in FIG. 3C, when a data file is downloaded from the host 21, the data file is added to or updated in the data area of the FROM 6. Accordingly, the information in the file management area on the SDRAM 5 side is updated. Then, as shown in FIG. 3D, when the portable information terminal 1 is powered off, the information in the file management area on the SDRAM 5 side is transferred to the FROM 6 side. When a predetermined time elapses, the work area information on the SDRAM 5 side is also transferred to the FROM 6 side. Note that the processing of the case shown in FIG. 3D will be described in detail later.

FIG. 2 is a flowchart showing the contents of control mainly performed by the microcomputer 4 with respect to the portion related to the gist of the present invention. Note that the portable information terminal 1 is assumed to be powered on. Whether the microcomputer 4 is operated by the user to move to the power-off state (step S3), or is it assumed that the battery cover of the main body is opened by the detection switch 19 and the battery 2 is removed (step S2)? Further, the battery 2 is consumed, the main power supply voltage is lowered, and the voltage monitoring circuit 10 waits until the “low battery” state is detected (step S1).
And when shifting to power-off (step S3, "YES"), all perform step S4-S12 as follows. FIG. 4 is a timing chart showing processing at power-off.

First, as shown in FIG. 3D, the microcomputer 4 transfers the information in the file management area on the SDRAM 5 side to the FROM 6 side (see step S4, FIGS. 4A and 4B). For example, if the capacity of the file management area is 32 kB, data transfer takes about 600 ms. Then, for example, the microcomputer 4 enables the interrupt generated by the RTC 8 every minute, stops the operation clock, and shifts to the sleep mode (step S5).
The microcomputer 4 is once activated by an interrupt generated every minute generated by the RTC 8 and counts the number of interrupts, and then enters the sleep state again. Then, when the count value becomes “10” and 10 minutes have passed (step S6, “YES”), the microcomputer 4 wakes up (step S7) and transfers information on the work area of the SDRAM 5 to the FROM 6 side (step S7). S8, see FIGS. 4A and 4B). For example, if the capacity of the work area is about 1 MB, data transfer takes about 10 seconds. Then, the microcomputer 4 sets the low level data in the flip-flop 17 to turn off the FET 15 and stop the backup of the SDRAM 5 (see step S9, FIG. 4 (e)).

Here, the time “10 minutes” in step S <b> 6 returns to the state immediately before the previous power-off when the user operates the power switch 23 to power-on the portable information terminal 1 during that time. This is the time set to execute the resume function quickly. That is, since the SDRAM 5 is backed up for 10 minutes and the work area information is held as it is, the microcomputer 4 can immediately operate based on the work area information.
In step S8, since the work area information is transferred to the FROM 6, even if the backup of the SDRAM 5 is stopped and the information on the SDRAM 5 is lost, it is retained on the FROM 6 side when the power is turned on again. If the information is transferred to the SDRAM 5 side, the resume function can be realized as described above.

  Then, the microcomputer 4 outputs a low level signal to the OR gate 24 to stop (turn off) the main power supply (step S10). Therefore, the backup of the SDRAM 5 is actually stopped at this point. Thereafter, the backup of the RTC 8 is continued through the sub-battery 12 until the battery 2 is completely consumed (step S11, “YES”) (step S12). The backup period is, for example, one month or more (see FIG. 4G).

On the other hand, when the microcomputer 4 detects that the battery cover is opened by the detection switch 19 from the state in which the portable information terminal 1 is powered on, for example, when the user intentionally opens the battery cover of the main body Or the case where a battery cover opens by applying external force to the portable information terminal 1 is assumed. In this case, the battery 2 may be removed from the storage unit, or the battery 2 may be dropped from the storage unit due to the impact of an external force, and there is a high possibility of shifting to a state where the main power supply is shut off. . Accordingly, the microcomputer 4 determines “YES” in step S2 in the above case, proceeds to step S13, and performs the same processing as step S4 (see FIGS. 5A and 5B). A timing chart corresponding to this case is shown in FIG.
Then, the microcomputer 4 turns off the main power supply by the power supply circuit 3 to put it in the power off state (step S14), and switches the operation power supply to the sub battery 12. Thereafter, even if the battery 2 is actually removed (see FIG. 5C), the backup function of the SDRAM 5 is maintained by the sub-battery 12 for a predetermined time, so that the resume function is effective (see FIG. 5D). ).

  When the SDRAM 5, RTC 8, flip-flop 17 and the like are backed up only by the sub-battery 12, the sub-battery 12 is gradually consumed and the backup power supply voltage gradually decreases. When about 10 minutes have passed and the operation limit voltage of the SDRAM 5 has fallen below 2.7 V (step S15, “YES”), the SDRAM 5 cannot be backed up at that time. At this time, the detection output of the voltage detection circuit 7 becomes low level, and the flip-flop 17 is reset. Then, the FET 15 is turned off, and the supply of backup power to the SDRAM 5 is stopped (step S16).

  Thereafter, the backup of the RTC 8 and the flip-flop 17 is performed by the sub-battery 12, but when about one hour has passed as it is (step S17, “YES”), the sub-battery 12 is further consumed and the backup is impossible. (Step S12). In the case of FIG. 5, the data on the SDRAM 5 can be saved in the FROM 6 only in the file management area. Therefore, it is possible to read out the control program and data stored in the FROM 6, but the resume function is disabled. Also, when the “low battery” state is detected (step S1, “YES”), steps S13 to S17 are similarly executed.

FIG. 6 shows a special case. For example, when the mobile information terminal 1 is dropped and an impact is applied, the battery 2 is dropped after the power supply by the battery 2 is momentarily interrupted from the power-on state. It is a timing chart which shows the case where it did. FIG. 7 is a flowchart of the microcomputer 4 corresponding to FIG.
When an impact is applied to the portable information terminal 1, the main power supply may be momentarily interrupted due to the momentary contact between the electrode in the battery housing portion of the main body and the electrode of the battery 2. At this time, the voltage monitoring circuit 10 detects a low battery (P1), but the microcomputer 4 performs minimum processing such as saving the data in the cache to the SDRAM 5. Then, the microcomputer 4 temporarily stops its operation (P3) due to the interruption of the main power supply (P2).

  Thereafter, the supply of the main power supply is resumed (P4), but the microcomputer 4 remains in the operation stopped state, and when the RTC 8 generates an interrupt that is output at intervals of 1 second (P5), the operation of the microcomputer 4 is stopped. The state is released and restarted (P6, start). Then, the microcomputer 4 determines whether or not the activation factor is due to the RTC8 interrupt (step S21). If the activation factor is due to the RTC8 interrupt ("YES"), the processing after step S13 shown in FIG. 2 is executed. To do. Therefore, the subsequent processing is the same as that in the timing chart of FIG.

As described above, according to the present embodiment, when the microcomputer 4 detects that the battery cover of the main body is opened by the battery cover open detection switch 19, the microcomputer 4 stores the information in the file management area in the stored contents of the SDRAM 5 in the FROM 6. When the transfer is completed, the main body is turned off, the power supply for operation is switched from the battery 2 to the sub-battery 12, and the backup to the SDRAM 5 is continued for a predetermined time. Therefore, it is possible to reliably avoid the loss of information necessary for managing the data file in the FROM 6 and to maintain the stored contents of the SDRAM 5 more reliably. In addition, since the data transfer is performed while the operation power is supplied from the battery 2, the transfer can be reliably completed while the power is stable.
After the transfer is completed, the main body is turned off, the operation power supply is switched to the sub-battery 12, and the backup to the SDRAM 5 is continued for a predetermined time. That is, since it is assumed that the user powers on the terminal again after the portable information terminal 1 is powered off, if the backup of the SDRAM 5 is continued, the data held on the SDRAM 5 is read immediately. Thus, the operating state before the power is turned off can be restored immediately.

  Further, when the RTC 8 backed up by the sub-battery 12 has a current value required for the backup smaller than that of the SDRAM 5 and can operate up to a voltage lower than that of the SDRAM 5, the microcomputer 4 determines that the voltage of the sub-battery 12 has a lower limit value. If it falls below, the backup to the SDRAM 5 is stopped, so that the time for backing up the stored contents of the RTC 8 can be secured longer. The RTC 8 preferably retains the setting data as much as possible in order to continue the time measurement based on the date and time data once set. Therefore, the present invention can be effectively applied to the portable information terminal 1 including the RTC 8.

Further, when the power off key of the main body is pressed while the battery 2 is stored in the storage unit, the microcomputer 4 transfers the information of the file management area on the SDRAM 5 to the FROM 6, and after the transfer is completed, the main body When a predetermined time elapses thereafter, the sleep state of the main body is canceled and the work area information is transferred to the FROM 6, and then the backup to the SDRAM 5 is stopped and the main body is turned off.
That is, even if the main body is turned off by the user's intention, there is a possibility that it will be turned on again. Therefore, the file management area information on the SDRAM 5 is also transferred to the FROM 6 and then the main body is put into the sleep state. Therefore, the information on the memory can be quickly read out within a predetermined time during which the SDRAM 5 is backed up. Further, since the data transfer in this case is also performed while the operation power is supplied from the battery 2, the transfer can be completed with certainty.

  After that, when a predetermined time elapses, it is important to make sure that the work area information on the SDRAM 5 is backed up. After the sleep state of the main body is canceled and the information is transferred to the FROM 6, the backup to the SDRAM 5 is stopped. . Therefore, when the SDRAM 5 is also used as a work area, the information in the file management area is preferentially saved, and the information in the work area is saved at the time when the possibility that backup to the SDRAM 5 cannot be maintained becomes high. Information can be backed up step by step according to the nature.

The present invention is not limited to the embodiments described above and shown in the drawings, and the following modifications or expansions are possible.
The volatile memory is not limited to the SDRAM 5, but may be a DRAM, an SRAM, or the like.
The nonvolatile memory is not limited to the FROM 5, but may be an EEPROM, an Fe (Ferroelectric) RAM, an M (Magneto resistive) RAM, or the like.
Other devices to be backed up by the backup power source are not limited to the RTC 8, and may be other devices such as a timer IC.
The portable information terminal is not limited to a barcode handy terminal, and any portable information terminal can be used as long as it has a volatile memory and a nonvolatile memory.

The figure which is one Example of this invention and shows only the part which concerns on the electrical structure of a portable information terminal concerning the summary of this invention The flowchart which shows the control content mainly performed by the microcomputer of the portable information terminal with respect to the portion according to the gist of the present invention. When the portable information terminal is powered off in the initial state (a), during the transition to power on (b), data file download (c), and power off processing (d), FROM and SDRAM Of memory image Timing chart showing processing at power-off Timing chart showing processing when the battery is removed from the portable information terminal Timing chart showing the processing when the battery falls out after a momentary interruption of the main power supply The flowchart which shows the process corresponding to the timing chart of FIG.

Explanation of symbols

  In the drawings, 1 is a portable information terminal, 2 is a battery, 4 is a microcomputer (control means), 5 is SDRAM (volatile memory), 6 is a flash ROM (nonvolatile memory), 8 is a real-time clock IC (RTC), Reference numeral 12 denotes a sub-battery (backup power supply), and 19 denotes a detection switch (battery cover open detection means).

Claims (4)

A battery for supplying power for operation;
Battery lid open detecting means for detecting that a battery lid for opening and closing a storage portion for storing the battery in the main body is opened;
Non-volatile memory where data files downloaded from outside are written,
A volatile memory in which a management area for managing data files on the nonvolatile memory is updated and set at the time of the download;
A backup power source for backing up the volatile memory;
Controlling data transfer between the volatile memory and the nonvolatile memory, and a control means for controlling a backup state for the nonvolatile memory,
When the battery cover open detecting means detects that the battery cover is opened, the control means transfers at least the information of the file management area to the nonvolatile memory among the contents stored in the volatile memory. After the transfer is completed, the portable information terminal is characterized in that the main body is turned off, the operation power supply is switched from the battery to the backup power supply, and the backup to the volatile memory is continued for a predetermined time. When the storage contents are backed up by the backup power source, and the current value required for the backup is smaller than the volatile memory and has a device operable to a voltage lower than the volatile memory,
Voltage detecting means for detecting the voltage of the backup power supply;
2. The portable information terminal according to claim 1, wherein the control means stops backup to the volatile memory when the voltage of the backup power source falls below a lower limit value.   The portable information terminal according to claim 2, wherein the device is a real-time clock IC that performs timekeeping. The volatile memory is also used as a work area during normal operation,
The control means, when the power off key of the main body is pressed in a state where the battery is stored in the storage unit,
Of the stored contents of the volatile memory, at least information on the file management area is transferred to the nonvolatile memory, and after the transfer is completed, the main body is put into a sleep state,
After a predetermined time has elapsed, the sleep state of the main body is released, the work area information is transferred to the non-volatile memory, the backup to the volatile memory is stopped, and the main body is turned off. The portable information terminal according to claim 1, wherein the portable information terminal is a portable information terminal.

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