JPH0744376A - Start program protecting method - Google Patents

Abstract

PURPOSE:To prevent an illegal program, which is prepared without any permission, from being started by preventing a prescribed program from being started when it is detected that data are not stored. CONSTITUTION:When using an electronic equipment by a user after factory forwarding, a CPU 12 executes an operating system(OS) stored in an OS RAM 14 and it is discriminated while referring to an initialization end flag of a prescribed address on a memory 18 whether this flag is set or not. When the initialize flag is set, data are read from the write area of system data in a memory 18, and by investigating whether these data are the same as the system data written by initialize processing or not, it is investigated whether the system data are existent on the memory 18 or not. When there are the relevant system data, an application program is not executed but processing is immediately finished. Thus, the electronic equipment can be prevented from being operated by any program excepting for the regular program.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of starting a predetermined program, and more particularly to a method of protecting a starting program for protecting the program from unauthorized exchange, unauthorized alteration / decoding, etc.

[0002]

2. Description of the Related Art Recently, many electronic devices and industrial devices incorporating a microcomputer have been remarkably intelligentized. In such a microcomputer-embedded device, it is possible to have multiple functions or individual functions by controlling the program.

For this reason, the contents of the program written in the ROM (Read Only Memory) of the microcomputer incorporated in the device are important confidential matters for each company, and the program has a particularly important function. If the program is fulfilled, illegally decrypting or copying the program will reduce the reliability of the product.

Further, it is also a great pain for a company that a ROM in which a program is written is improperly replaced so that some functions can be added or functions can be changed.

[0005]

[Problems to be Solved by the Invention] However, in the past,
In a device incorporating the microcomputer as described above, a program (for example,
The actual situation is that sufficient protection measures have not been taken against illegal decryption and copying of application programs. Further, sufficient protection is not provided even against improper replacement of the ROM in which the program is written.

In view of the above-mentioned circumstances, the present invention prevents a device from operating unless it is a legitimate program that should be originally installed in the device, in other words, an unauthorized program created without permission. The purpose is to make it unbootable on the device.

Another object of the present invention is to prevent the normal operation of the device when the ROM in which the program is written is taken out in an attempt to illegally modify the device.

Still another object is to prevent the program written in the ROM mounted on the device from being decrypted to prevent the creation of an unauthorized program (software).

[0009]

The invention according to claim 1 is
Predetermined data is written in the memory, when starting a predetermined program, it is detected whether or not the data is stored in the memory, and when it is detected that the data is not stored, The predetermined program is not activated.

The predetermined program is, for example, a program installed in advance in a certain electronic device. The invention according to claim 2 is the same as the invention according to claim 1,
The writing of the data is performed by executing a program loaded from the outside, and the program is erased after the execution is completed.

The program is loaded from an external storage device such as a floppy disk device or a hard disk device. According to a third aspect of the present invention, in the first aspect of the present invention, the memory is a volatile memory and has at least a component carrier on which the memory is mounted and a power supply for supplying a power supply voltage to the memory. A power supply path from the power supply to the memory is provided between the component carrier and the substrate, and the power supply path is shut off when the space between the component carrier and the substrate is opened. It is characterized by

The power supply path includes, for example, a connector or screws. The component carrier may be, for example, a printed circuit board. According to a fourth aspect of the present invention, in the first aspect of the present invention, the memory is a volatile memory, has a power supply for supplying a power supply voltage to the memory, and an electronic component for storing programs and the like. A switch is provided between the boards on which the electronic parts are mounted, and when the electronic parts are removed from the board, the supply of power to the memory is cut off due to a change in the state of the switch.

The electronic component is, for example, a ROM (Read Only Memory) in which an application program for incorporating an electronic device is written. According to a fifth aspect of the present invention, in the first aspect of the present invention, the memory is a volatile memory, and has at least a substrate on which the memory is mounted and a battery that supplies power to the memory. Is sandwiched between the substrate and a base body covering the substrate, and when the gap between the substrate and the base body is opened,
The battery is dropped.

The substrate may be, for example, a printed circuit board. According to a sixth aspect of the present invention, there is provided an erasable ROM that stores a program or data, and a component carrier on which an erasing device that erases the stored contents of the erasable ROM is mounted. When a gap between the component carrier and the component carrier is opened, a detection switch for detecting this is provided, and in response to a change in the state of the detection switch, the erasing device is driven to change the stored contents of the erasable ROM. It is characterized by erasing.

The erasable ROM is, for example, an ultraviolet erasable EPROM (Erasable Programmable ROM). In this case, the erasing device is an ultraviolet irradiation device such as a strobe discharge tube for irradiating ultraviolet rays. The detection switch is, for example, a micro switch. The erasable ROM is, for example, an EEPROM (El
ectrically Erasable Programmable ROM).

[0016]

In the invention described in claim 1, the predetermined data is written in the memory (hereinafter referred to as a data memory for convenience). When starting the predetermined program, it is detected whether or not the data is stored in the data memory, and if the data is not stored, the predetermined program is not started.

Therefore, for example, a predetermined program for controlling the microcomputer, which is incorporated in a microcomputer-controlled (hereinafter referred to as microcomputer-controlled) electronic device, is decoded or modified, and further replaced with another program. For the purpose of unauthorized use, when the memory in which the predetermined program is written (hereinafter referred to as a program memory for convenience) is to be removed from the board in the electronic device, the memory is stored in the data memory. If the above-mentioned data is erased, it is possible to prevent the above electronic device from operating normally after the above-mentioned illegal actions. In other words, it is possible to prevent the electronic device from operating with a program other than a legitimate program.

According to the second aspect of the invention, the writing of the predetermined data to the memory is performed.
It is performed by executing a program loaded from the outside, and the program erases immediately after the completion of the execution.

Therefore, by performing the above-described data writing process at the time of factory shipment, it becomes almost impossible for a third party to write the predetermined data into the memory after the product is shipped. Therefore, as described above, the above data is erased when the memory in which the predetermined program is written is removed from the board in order to modify the device improperly. If you do something wrong,
You can prevent the device from working properly.

According to another aspect of the invention, a volatile memory is used as the data memory, and at least a component carrier on which the data memory is mounted and a power supply for supplying a power supply voltage to the data memory are provided. further,
A power supply path from the power supply to the data memory is provided between the component carrier and the substrate. Then, when the gap between the component carrier and the substrate is opened, the power supply path is shut off. For this reason, the supply of the power supply voltage to the data memory is interrupted, so that the data stored in the data memory is erased.

Therefore, when the program memory is mounted on the board and the program memory is taken out from the board, the space between the component carrier and the board is always opened and the power supply path is cut off. With such a configuration, the same effect as the invention according to claim 1 can be obtained.

According to a fourth aspect of the present invention, a volatile memory is used as the data memory, a power supply for supplying a power supply voltage to the data memory is provided, and an electronic component storing a program and the electronic component are provided. A switch is provided between the board and the mounted board. Then, when the electronic component is removed from the substrate, the supply of the power supply voltage to the memory is interrupted by the change of the state of the switch. As a result, the data stored in the data memory is erased.

Therefore, if the program memory is removed from the board in an attempt to illegally modify, exchange or decode the predetermined program by using the electronic component as the program memory, for example, For this reason, the electronic device in which the program memory is mounted will not operate normally thereafter.

According to the invention of claim 5, a volatile memory is used as the data memory, at least a substrate on which the data memory is mounted and a battery for supplying a power supply voltage to the data memory are provided, and the battery is the above-mentioned battery. It is configured to be sandwiched between the substrate and the base body. Therefore, when the space between the substrate and the base body is opened, the battery is dropped, and thereby the data stored in the data memory is erased.

Therefore, when the program memory is mounted on the substrate and the program memory is to be removed from the substrate, the configuration is such that the substrate and the base body are always opened. As a result, the same effect as the invention according to claim 1 can be obtained.

According to a sixth aspect of the present invention, an erasable ROM for storing a program or data and an erasing device for erasing the stored contents of the erasable ROM are provided with a component carrier, and the component carrier is further provided. A detection switch is provided to detect when a gap between the base body covering the body and the component carrier is opened. Then, in response to the state change of the detection switch, the erasing device is driven to erase the stored contents of the erasable ROM.

Therefore, if the erasable ROM stores a program to be incorporated in a microcomputer-controlled electronic device, when the base is opened in an attempt to decode the program, the detection switch operates, The erasing device erases the program written in the ROM. Then, this makes it impossible to decipher the program.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit block diagram showing a system configuration of an electronic device according to an embodiment of the present invention.

In the figure, the circuit 10 surrounded by a broken line is mounted on one or a plurality of printed circuit boards or the like. The circuit 10 includes a CPU 12, an OS. ROM 16, IP. RAM 18, memory 18, AP. ROM 20 and I / O controller 22
Is equipped with.

OS. The ROM 16 is, for example, a mask ROM
ROM such as (mask Read Only Memory)
An operating system (OS) executed by the CPU 12 is stored.

IP. The RAM 16 stores an initialization program input via the I / O controller 22.
It is AM (random access memory). Memory 1
A volatile memory 8 is supplied with a power supply voltage from an external power supply circuit 40 which is usually a main power supply. Then, when the switch 42 of the power supply circuit 40 is turned off and the supply of the power supply voltage from the power supply circuit 40 is interrupted, the data is supplied by receiving the supply of the power supply voltage from the battery 24 which is a backup power supply, for example, a secondary battery. Hold. The positive electrode of the battery 24 is connected to the anode of the diode 26, and the power supply voltage from the battery 24 is supplied to the memory 18 via the diode 26 and the switch 28.
Is supplied to. On the other hand, the power supply voltage from the power supply circuit 40 is supplied to the memory 18 via the power supply switch 42, another diode 30 and the switch 28.

AP. The ROM 20 is a ROM in which a predetermined application program is written, and data can be collectively erased by irradiation of ultraviolet rays, and data can be rewritten in EPROM (Erasable and Programmabl).
e Read Only Memory).

The I / O controller 22 controls input / output of data between the CPU 12 and an external storage device such as a floppy disk device or a hard disk device or other peripheral devices.

The power supply circuit 40 is a stabilized DC power supply including, for example, a switching power supply (Switing Power Suplly), and in addition to the memory 18, the CPU 12, OS. RO
M14, IP. RAM16, AP. ROM 20 and I /
The DC power supply voltage is supplied to the O controller 22.

Next, the operation of the electronic device having the above configuration will be described with reference to the flowchart of FIG. First, before shipment, this electronic device performs SA processing surrounded by a broken line in FIG.

This processing SA is AP. This is a system initialization process for preventing the illegal replacement of the ROM 20. First, when the power switch 42 is turned on, the CPU 1
2 is OS. The OS (operating system) stored in the ROM 14 is executed, and first, it is determined whether or not the initialization end flag is set by referring to a predetermined address in the memory 18 (SA1). This initialization end flag is, for example, a 1-bit flag.

At this stage, since the initialization end flag has not been set yet (SA1, NO), the initialization program is executed from the external storage device (not shown) via the I / O controller 22. Load to RAM16 (SA
2).

The CPU 12 subsequently activates this initialization program (SA3), and by executing this initialization program, writes predetermined system data to a predetermined area of the memory 18 (SA4). This system data is
For example, it is a predetermined character string of several words.

Then, IP. The initialization program loaded on the RAM 16 is erased (SA5), and then the initialization completion flag at a predetermined address of the memory 18 is set (SA6).

By the system initialization processing SA as described above, the initialization completion flag is set when the electronic device is shipped from the factory, and the system data is written in a predetermined area of the memory 18. There is. Incidentally, the battery 24 is mounted at the time of factory shipment, the switch 28 is also set to ON, and the memory 18 is backed up, so that the system data and the state of the initialization end flag written in a predetermined area of the memory 18 are retained. .

Next, the operation of the electronic device when it is used by the user after shipment from the factory will be described with reference to the flowchart of FIG. When the user turns on the power switch 42 to use the electronic device, the power supply circuit 40 supplies the power supply voltage to all the electronic components of the circuit 10 surrounded by the broken line in FIG. R
The operating system stored in the OM 14 is executed. As a result, the CPU 12 first causes the memory 18
By referring to the initialization end flag of the above predetermined address, it is determined whether or not this initialization end flag is set (S
A1).

If the initialization flag is set (SA1, YES), data is read from the system data writing area of the memory 18 (SB1), and this data is the same as the system data written by the processing SA. It is checked whether or not there is system data in the memory 18 by checking whether or not (SB2).

If the corresponding system data is present, AP. The application program is read from the ROM 20 and the application program is activated (SB3).

As described above, the application program stored in the AP ROM 20 is executed only when the initialization end flag is set in the memory 18 and the corresponding system data is written.

On the other hand, if there is no corresponding system data in step SB2, the application program is not executed and the process is immediately terminated.
In the present embodiment, as will be described later, after the factory shipment, the AP. When an illegal act such as removing the ROM 20 from the printed circuit board is performed, the contents of the memory 18, that is, the system data is erased.

Therefore, when the above-mentioned unjust acts are performed, the AP. The application program stored in the ROM 20 cannot be started. Further, in the present embodiment, since the initialization flag and the system data are double-checked, the above-mentioned unjust acts are strictly prohibited. This is also because when the initialization end flag is a bit flag, the above initialization flag is accidentally (a human error or a soft error due to α rays) or the This is also a countermeasure for this because it may be set.

In order to further improve safety, as described above, after the initialization program is executed and the initialization end flag is set before shipment from the factory,
Immediately, the initialization program is erased, and a measure is taken so that the purchaser of this electronic device cannot use the initialization program (SA in the flowchart of FIG. 2).
5).

Next, mounting examples of the embodiment having the configuration shown in FIGS. 1 and 2 are shown in FIGS. FIG. 3 is a side view showing an example of the mounting form of this embodiment. In the figure, the lower printed circuit board (PCB) on which the memory 18 is mounted
An upper printed circuit board (PCB) 60 on which the battery 50 and the battery 24 are mounted is fixed by screws 70 at its four corners so as to face each other. Also, PCB5
0 and PCB 60 have male connectors 80 in the center.
D and a female connector 80U are vertically provided. In the fixed state, the connector 80D and the connector 80U are fitted and connected to each other.

Male connector 8 hung vertically on PCB 50
OD is a printed wiring 52 formed on the PCB 50.
Is connected to the terminal Vcc of the memory 18 via. On the other hand, the female connector 80U vertically mounted on the PCB 60 is
Through the printed wiring 62 formed on the CB 60, the positive electrode of the battery 24 and the power switch 42 of the power circuit 40.
It is connected to the. Further, the battery 24 is supported at its end by a support 90 embedded in the PCB 60 so as not to fall off from the PCB 60. Although not shown in the figure, AP. The ROM 20 is also mounted.

In the above structure, the male connector 80D and the female connector 80U correspond to the switch 28 shown in FIG. Since the mounting state as described above is set, the PCB 50 changes the AP. In order to remove the ROM 20, it is necessary to open the PCB 50 after removing the screw 70 from the PCB 50 and the PCB 60. However,
When the PCB 50 is opened in this way, the male connector 80
The D and the female connector 80U are disengaged, and the supply of the power supply voltage from the battery 24 or the power supply circuit 40 to the memory 18 is cut off. As a result, the stored contents of the memory 18 are all erased. As a result, the system data written in the memory 18 is erased and the initialization end flag is reset.

Therefore, AP. For the purpose of illegally modifying the application program written in the ROM 20, the AP. When the ROM 20 is taken out of the device, the device will not operate normally thereafter. Therefore, it becomes impossible to start an unauthorized application program created without permission on this device.

The PCB 60 may be, for example, the upper case of the device. Next, FIG. 4 is shown in FIG. 1 and FIG.
It is a figure which shows the other example of mounting of the Example shown in FIG. As shown in FIG. 3A, the surface of the printed wiring board (PCB) 101 has the memory 18, AP. The ROM 20 and the like are mounted, and a through hole is provided as shown in the center of FIG. As shown in FIG. 2B, a ring-shaped front surface pad (conductor land) 102 and a rear surface pad (conductor land) 103 are formed on the front surface and the back surface of the PCB 101 around the through hole, respectively. The diameters of these pads 102 and 103 are larger than the diameter of the through holes, and these pads 102 and 103 are not electrically connected to each other through the through holes. The surface pad 103 is a PCB 101.
It is electrically connected to the memory 18 by a printed wiring (not shown) formed on the surface portion of the. On the other hand, the back surface pad 102 is electrically connected to the cathodes of the diode 30 and the diode 26 shown in FIG. 1 via the printed wiring (not shown) and the through holes (not shown) formed on the back surface and the front surface of the PCB 101. .

The front side of the PCB 101 is the case 120.
Are covered by. Hollow protrusion 12 of the case 120
The inner diameter side of 1 is hollow, and an insert nut 123 made of a conductive member is embedded in the hollow. Then, the PCB 101 and the case 120 are
The case 12 is inserted through the through hole of the PCB 101.
It is fixed by screwing a screw 140 made of a conductive member into the insert nut 123 in the hollow protrusion 121 of No. 0. In this screwed state, a spring 125 made of a conductive member is interposed between the insert nut 123 and the surface portion of the PCB 101 facing the insert nut 123. Also, in this fixed state, screws 1
The head of 40 is the back surface side of the PCB 101 and the back surface pad 1
It is in contact with 03. Therefore, in this way PCB1
01 and the case 120 are fixed to each other by the screw 140 and the insert nut 123, the back surface pad 102 and the front surface pad 103 are electrically connected via the screw 140, the insert nut 123, and the spring 125. The memory 18 is supplied with the power supply voltage from the power supply circuit 140 and is backed up by the battery 24.

In the above structure, the pads 102, 10
3, the insert nut 121, the spring 125, and the screw 140 correspond to the switch 28 shown in FIG. As described above, AP. Since the ROM 20 is mounted on the front surface side of the PCB 101, the AP. ROM20 to PCB1
To remove the screw from 01, it is necessary to remove the screw 140. However, when the screw 140 is removed, the screw 140
Backside pad 102 and frontside pad 1 that were electrically connected via
Since 03 is in a non-conducting state, the supply of power supply voltage from the power supply circuit 40 and the battery 24 to the memory 18 is cut off, and the stored contents of the memory 18 are all erased.

As described above, even in the implementation example shown in FIG. ROM 20 to another AP. For unjustified purposes such as exchanging with ROM, the AP. ROM20 to PCB101
Once removed, the electronic device will no longer work.

Next, FIG. 5 is a diagram showing still another mounting example of the embodiment having the configuration shown in FIGS. 1 and 2. In this example, as shown in FIG. 5A, the AP. ROM2
1 Insert the IC socket 220 for insertion. A micro switch 230 corresponding to the switch 28 of FIG. 1 is mounted inside the IC socket 220. The height of the push button 231 of the micro switch 230 is the same as that of the AP. The height is set so that when the ROM 21 is inserted, the micro switch 230 is pressed and turned on.

Therefore, since the switch 28 shown in FIG. 1 is turned on at the time of factory shipment, the memory 18 mounted on the PCB 210 is supplied with a predetermined constant voltage from the battery 24 which is a backup power source. Therefore, the system data written in the memory 18 is held, and the initialization end flag is also held in the set state.

After the factory shipment, a purchaser
P. If the ROM 20 is illegally used by another AP. For illegal purposes such as trying to replace the ROM, the AP. ROM20 to I
When it is removed from the C socket 220, the micro switch 2
30 is turned off, and the supply of the power supply voltage from the power supply circuit 40 and the battery 24 to the memory 18 is cut off. Then, as a result, all the stored contents of the memory 18 are erased, so that the system data is also erased and the initialization end flag is also reset.

Therefore, the same effect as the example shown in FIGS. 3 and 4 can be obtained. Next, as shown in FIG.
FIG. 7 shows a mounting example in which the power supply for supplying the power supply voltage to the memory 18 in the circuit shown in FIG.

In the figure, a printed circuit board (PCB) 250 on which the memory 18 is mounted and another printed circuit board (PCB) 260 have screws 270 at their four corners.
They are screwed together and fixed to each other at a predetermined distance.

In this fixed state, the elastic member 280 is mounted on the PCB 250, and the battery 24 is sandwiched between the elastic member 280 and the PCB 260. The memory 18 mounted on the PCB 250 and the battery 24 are electrically connected to each other by a printed wiring 252 formed on the PCB 250 and a wiring member (not shown) fixed to the surface of the elastic member 280. It is designed to be backed up from the battery 24. Although not shown in the figure, A
P. The ROM 20 is also mounted. Therefore, the AP. R
In order to take out the OM 20, one of the PCB 250 and the PCB 260 screwed by the screw 270 must be opened. In the above configuration, the contact portion between the positive terminal of the battery 24 and the wiring member (not shown) fixed to the elastic member 280 corresponds to the switch 28 of FIG.

Then, while in the state shown in FIG. The ROM 20 is improperly assigned to another AP. For illegal purposes such as trying to replace it with ROM, remove screw 270,
When the PCB 260 or the PCB 250 is opened, the battery 24, which is mounted on the elastic member 280 in an unstable state, drops off from the elastic member 280, and the supply of the power supply voltage from the battery 24 to the memory 18 is interrupted. This allows the memory 18
The system data stored in the memory is erased and the initialization setting flag is reset. As a result, similar to the example shown in FIGS. 3 to 5, even if the state shown in FIG. 7 is restored, the AP. ROM20
It becomes impossible to execute the application program written in. In addition, A was exchanged improperly
P. It also becomes impossible to execute the application program written in the ROM.

If a conductive member is used as the elastic member 280, the wiring member becomes unnecessary. Next, FIG. An attempt is made to illegally decode the program written in the ROM 20, or the AP. RO
M20 to another AP. It is a figure which shows the example of mounting of the electronic device which prevents illegal activities, such as trying to operate an electronic device by another application program, illegally exchanging for ROM.

In the figure, two PCBs 310 and PC
Similar to the example shown in FIG. 7 described above, the B320 has four corners screwed by screws 330 and is fixed at a predetermined distance.

On the PCB 310, an EPROM (Eras
A consisting of able and Programmable Read Only Memory)
P. The ROM 20 is mounted. In addition, the AP. RO
When a power of about 15 W is supplied to the M20, it irradiates with an ultraviolet ray having a wavelength of about 2357Å for about 0.96 seconds. R
A flash discharge tube 340 for erasing data stored in the OM 20 is mounted and fixed. Further, the PCB3
Between the PCB 10 and the PCB 320, one end is the PCB
An insulative member 350 fixed to 320 is sandwiched, and the first conductive member 3 having rigidity that is partially fixed on the PCB 310 on both sides of the insulative member 350.
The tips of the second conductive member 370 and 60 are in contact with each other. The tips of these conductive members 360 and 370 are bent in a semicircular shape so as to have elasticity. Therefore, when the insulating member 350 is removed, the tips of the two conductive members 360 and 370 come into contact with each other. That is, the three members 350,
Reference numerals 360 and 370 form one detection switch.

The other end of the conductive member 360 is connected to the power input terminal of the stroboscopic discharge tube 340, and the other end of the other conductive member 370 is connected via a printed wiring formed on the PCB 310. It is connected to the battery shown.

Thus, the AP. ROM20 is PCB
Since it is interposed between 310 and PCB 320, A
P. In order to take out the ROM 20, it is necessary to remove the screw 330 and open the PCB 320. However, if such an action is performed, the insulating member 350 is also pulled out together with the PCB 320, so that the tips of the conductive member 360 and the conductive member 370 come into contact with each other for the above-described reason, and the strobe discharge tube 340 is exposed. Driving power of about 15 W is supplied from the battery. As a result, the strobe discharge tube 340
From EP. The ultraviolet ray transmission window of the ROM 20 is irradiated with ultraviolet rays having a wavelength of approximately 2357Å for approximately 0.96 seconds, and A
P. The contents written in the ROM 20, that is, the contents of the application program are all erased. Therefore, the AP. The application program written in the ROM 20 cannot be decrypted.

In this example, AP. EP in ROM20
Although ROM is used, instead of EPROM, for example, EEPROM (Electrically Erasable Programmable R
OM) may be used. In this case, for example, the PC
Provided with a switch that detects that B320 has been opened,
The microprocessor receives the signal from the detection switch and erases the contents stored in the EEPROM.

As a modification of the example shown in FIG. 5,
When the AP. ICs other than ROM20
(For example, the memory 18) is inserted, and the EPROM or EEP is detected by the detection signal of the microswitch 230 when the IC is pulled out from the IC socket 220.
AP consisting of erasable ROM such as ROM. ROM20
It is also possible to erase all the stored contents of. With such a configuration, the memory 1 is attached to the IC socket 220.
If the electronic device after shipment is tampered with, the AP. Not only the contents of the ROM 20 but also the contents of the memory 18 can be erased at the same time.

[0070]

As described above, according to the first to fifth aspects of the present invention, predetermined data is written in the memory and the data is stored in the memory when a predetermined program is started. Is detected,
When it is detected that the data is not stored, the predetermined program is not started, so that an unauthorized program created without permission is not started in the microcomputer controlled electronic device. You can do it (you can prevent it from running unless it is a legitimate program). Further, when the inside of the electronic device is opened in an attempt to illegally modify the electronic device, the electronic device can be prevented from operating normally thereafter.

According to a sixth aspect of the present invention, there is provided an erasable ROM for storing a program or data, and a component carrier on which an erasing device for erasing the stored contents of the erasable ROM is mounted. A erasable ROM is provided by providing a detection switch for detecting a gap between the body covering the body and the component carrier, and driving the erasing device in response to a change in the state of the detection switch.
Since the contents stored in is deleted, it is possible to prevent the decryption of the program installed in the electronic device in which the microcomputer is incorporated and to prevent the creation of unauthorized software.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing a system configuration of an electronic device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating the operation of the CPU in the above embodiment.

FIG. 3 is a diagram showing a first implementation example of the above embodiment.

FIG. 4 is a diagram showing a second implementation example of the above embodiment.

FIG. 5 is a diagram showing a third implementation example of the above embodiment.

FIG. 6 is a diagram showing an example of a circuit in which a power supply for a memory includes only a battery.

7 is a diagram showing a mounting example of the memory and the battery when the power supply circuit for the memory has the configuration shown in FIG. 7. FIG.

FIG. 8: AP. It is a figure which shows the example of mounting when EPROM is used as ROM.

[Explanation of symbols]

10 Circuit of electronic device 12 CPU 14 OS. ROM 16 IP. ROM 18 memory 20 AP. ROM 22 I / O controller 24 Battery 28 Switch 40 Power supply circuit 42 Power supply switch 50, 60, 101, 210, 250, 260, 31
0,320 Printed circuit board (PCB) 70, 140, 270, 330 Screw 80D Male connector 80U Female connector 90 Support 102 Back pad 103 Surface pad 120 Case 121 Case protrusion 123 Insert nut 125 Spring 220 IC socket 230 Micro switch 252 Printed wiring 280 Elastic member 340 Strobe discharge tube 350 Insulating member 360 First conductive member 370 Second conductive member

Front page continuation (72) Inventor Sho Kumagai 3-2-1 Sakaemachi, Hamura-shi, Tokyo Casio Computer Co., Ltd. Hamura Technical Center

Claims (6)

[Claims] 1. Predetermined data is written in a memory, and when a predetermined program is started, it is detected whether or not the data is stored in the memory, and it is detected that the data is not stored. The boot program protection method is characterized in that the predetermined program is not booted when the program is booted. 2. The boot program protection method according to claim 1, wherein the writing of the data is performed by executing a program loaded from the outside, and the program is erased after the execution is completed. 3. The memory comprises a volatile memory,
At least a component carrier on which the memory is mounted and a power supply for supplying a power supply voltage to the memory are provided, and a power supply path from the power source to the memory is provided between the component carrier and the substrate. 2. The boot program protection method according to claim 1, wherein the power supply path is shut off when the gap between the carrier and the substrate is opened. 4. The memory comprises a volatile memory,
A switch is provided between an electronic component storing a program and the like and a substrate on which the electronic component is mounted, the switch having a power supply for supplying a power supply voltage to the memory, and when the electronic component is removed from the substrate. 2. The boot program protection method according to claim 1, wherein the power supply to the memory is shut off by changing the state of the switch. 5. The memory comprises a volatile memory,
At least a substrate on which the memory is mounted and a battery for supplying power to the memory are provided, and the battery is sandwiched between the substrate and a base body covering the substrate, and a space between the substrate and the base body is opened. The boot program protection method according to claim 1, wherein the battery is dropped when the battery is dropped. 6. A component carrier having an erasable ROM for storing a program or data and an erasing device for erasing the stored contents of the erasable ROM, a base for covering the component carrier, and the component. A detection switch is provided for detecting the distance between the carrier and the carrier, and the erasing device is driven in response to a change in the state of the detection switch to erase the contents stored in the erasable ROM. A boot program protection method characterized by: