JPH01197847A - Data protecting device - Google Patents

Abstract

PURPOSE:To prevent the influence exerted on data due to an abnormal operation, and also, to protect the processing data by resetting an operation of a CPU when read and write of the data are being executed and holding the operation of the CPU when read and write of the data are not being executed. CONSTITUTION:When an IC card 10 is drawn out of a connector 20 and a device main body 30 is executing read and write of the IC card 10 and data, a software reset is applied to a CPU 31. As a result, by drawing out the card, a program comes not to operate normally, and it can be prevented that processing data is broken down due to an abnormal operation of the CPU 31. On the other hand, when the IC card 10 is drawn out of the connector 20, and the device body 30 is not executing read and write of the IC card 10 and data, a software reset is not applied to the CPU 31, and its operation is held as it is. Accordingly, a noise generated by drawing out the card is eliminated by a bus buffer 50, and a malfuction is prevented. In such a way, the influence exerted on the data due to an abnormal operation can be prevented, and the processing data can be protected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data protection device applied to a data processing device to which a memory card such as an IC card can be connected.

[Prior Art] In recent years, a memory card such as an IC card is removably connected to a built-in memory such as ROM or RAM, and data is read and written to the memory card according to the program operation of the CPU. For example, data processing devices such as ECRs (preliminary cash registers) have been developed.

In such a device, if the memory card is removed from the card connector, if the CPU is reading and writing data to and from the memory card under program control, the program will not work properly and the CPU will operate abnormally. This may cause data to be destroyed. Furthermore, even if data is not being read or written to or from the memory card, noise generated when the card is removed may affect address signals and data signals of the processing device, causing the entire device to malfunction. For this reason, in conventional devices of this type, when the memory card is removed, the CP
A data protection device is provided that protects processed data by applying a reset to U.

FIG. 3 is a diagram showing a conventional data protection device, in which 1 is a memory card, 2 is a connector for the memory card, and 3 is a reset signal generation circuit connected to a reset terminal of a CPU. Memory card 1 to memory card connector 2
is installed, the terminal 1a inside the card is connected to the terminal 2a of the connector 2, and the terminal 1b inside the card is connected to the terminal 2a of the connector 2.
is connected to terminal 2b of connector 2. As a result, the input voltage V1n of the reset signal generation circuit 3 is at a low level. On the other hand, when the memory card 1 is removed from the memory card connector 2, the input voltage Vin of the reset signal generation circuit 3 becomes a noise level, thereby generating a reset signal, which is supplied to the reset terminal of the CPU and resets the CPU. It takes a reset.

[Problem to be solved by the invention] However, in the conventional data protection device described above,
Since the CPU is always reset when the memory card is removed, even if the CPU is performing an operation that does not use the memory card, the CPU is reset and the operation is interrupted, resulting in the loss of processed data. There was a problem.

Therefore, in the present invention, if data is being read from or written to the memory card when the memory card is removed, the
To provide a data protection device that can prevent data from being affected by abnormal operation by resetting a PU, and can protect processed data without resetting the CPU when data is not being read from or written to a memory card. It is something.

[Means for Solving the Problems] The present invention provides a CPU, a ROM, a RAM tt.
A memory card connector is connected via a bus line to a processing device main body having A bus buffer is interposed, and a card removal detection means detects that the memory card is removed from the memory card connector, and the memory card and the processing device main body are connected via the bus buffer in response to a card removal signal from this detection means. A determination means for determining whether or not data is being read or written; and a determination means for resetting the CPU operation if data is being read or written according to the result of the determination means; and if data is not being read or written, is C
A data protection means for maintaining the operation of the PU is provided.

[Function] With the device of the present invention having such a configuration, if the memory card is removed while data is being read or written between the memory card and the processing device main body, the CPU is reset and data destruction due to abnormal operation is prevented. be done. If you remove the memory card when the memory card and the processing unit are not reading or writing data, the CPU operation will be retained.
data is protected during processing. At this time, noise generated by card removal is removed by the bus buffer.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of the device of this embodiment, in which 10 is an IC card as a memory card, and 20 is the above-mentioned I/O card.
This is an IC card connector to which the C card 10 is detachably connected, and 30 is a data processing device main body that reads and writes data to and from the IC card 10 attached to the IC card connector 20. The data processing device main body 30 is a CPU (central processing unit) that performs calculation operations on input data, status determination operations, etc. under program control.
31. ROM that stores fixed data such as programs (
RAM (random access memory) 33 that stores variable data such as input data and arithmetic processing data, and input/output that drives and controls input/output devices such as keyboards, displays, and printers. It is composed of a controller 34. Further, the IC card connector 20 is connected to the address/data bus 41. They are connected via a read/write signal line 42 and a status signal line 43. The IC card 10 is connected to the address and data bus 41 and the read/write signal line 42.
A bus buffer 50 is interposed to remove noise generated when the C card connector 20 is removed.

Then, when the CPU 31 of the data processing device main body 30 monitors the status signal line 43 and detects that the signal level changes from high level to low level due to the insertion of the IC card 10, it recognizes that the card has been inserted. Execute the program processing shown in That is, the status signal line 43 is monitored as ST1, and if the IC card 10 remains attached, normal processing is executed.

In STI, when the signal level of the status signal changes from low level to high level and it is detected that the IC card 1o has been removed from the IC card connector 20, ST2
Then, it is determined whether data is being read from or written to the IC card 1o via the address/data bus 41. Here, if data is being read and written to the IC card 10, this IC card 1 is used as ST3.
The data read/write operation with ゜ is stopped, and the software is reset in ST4 to return to normal processing. On the other hand, in ST2, data is not read or written to or from the IC card and other processing is executed, and if ST2 is 1, the processing is continued without performing a software reset.

In this embodiment configured as described above, by attaching the IC card 1o to the IC card connector 20, it becomes possible to read and write data between the data processing device main body 3o and the IC card. In this state, when the IC card 1o is removed from the connector 2o, the main body 3o of the device is connected to the IC card 1.
CPU3 when reading and writing data with o.
1. Perform a software reset. As a result, the program will not work properly when the card is removed, and the CP
It is possible to prevent U31 from operating abnormally and destroying processed data.

On the other hand, if the device main body 30 is not reading or writing data to or from the IC card 10 when the IC card 10 is removed from the connector 20, the CPU 31 is not software reset and continues to operate as it is. The noise generated by card removal is handled by the bus buffer 50.
The signal is removed by , and malfunction is prevented without affecting the address signal or data signal. As a result, lC
Other processes that are being performed without the card 10 can continue and the data can be protected.

Therefore, according to this embodiment, data processing 1! ! Even if the IC card 10 is accidentally removed while the device main body 30 is being driven, data abnormality due to malfunction can be prevented, and processed data can be reliably protected.

[Effects of the Invention] As described in detail below, according to the present invention, if data is being read from or written to the memory card when the memory card is removed, the CPU is reset to prevent abnormal operation. It is possible to provide a data protection device that can prevent data from being affected by data, and can protect processed data without resetting the CPU when data is not being read or written to or from a memory card.

[Brief explanation of the drawing]

FIG. m1 is a diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a flow chart showing the main operations of the CPU in the same embodiment, and FIG. 3 is a diagram showing the configuration of a conventional example. 10...IC card (memory card), 20...I
C card connector, 30... data processing device main body, 3
1...CPU, 41...Address/data bus, 4
2... Read/write signal line, 43... Status signal line, 50... Bus buffer. Applicant's agent Patent attorney Takehiko Suzue 52 Figure 3

Claims (1)

[Claims] Connect the memory card connector to the processing device body including CPU, ROM, RAM, etc. via the bus line,
A bus buffer interposed on the bus line in a device for reading and writing data with a memory card detachably connected to the memory card connector;
a card removal detection means for detecting that a memory card has been removed from the memory card connector; and a card removal detection means for causing the memory card and the processing device main body to read and write data via the bus buffer in response to a card removal signal from the detection means. a determination means for determining whether data is being read or written; and a determination means for resetting the operation of the CPU when data is being read or written based on the result of the determination means; and resetting the operation of the CPU when data is not being read or written. 1. A data protection device comprising: data protection means for maintaining operation.