JPS634387A - Ic card - Google Patents

Abstract

PURPOSE:To obtain a high reliability under very adverse environments by allowing remaining control circuits and remaining nonvolatile memories to operate based on communications with a host computer even if a set of control circuit and set of nonvolatile memories are destructed. CONSTITUTION:After the execution time of self-diagnosis programs in microcomputer units MCU 1 and MCU 2 passes, the host computer HCU sequentially selects registers where fault and normal flags are set, sequentially reads stored data, and decides whether fault develops or not. If the host computer HCU decides that the fault flag is set to either one of the microcomputer units and the normal flag is set to the other, the computer HCU operates only the normal system by using the chip select signal of the system to which the fault flag is set as a constant inoperable level.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an IC card, such as an EEPRO card.
M (Electrically Erasable Programmable)
The present invention relates to a technology that is effective when applied to an IC card equipped with a single-chip microcomputer that includes a nonvolatile memory (such as a read-only memory) and a central processing unit.

[Prior art]

Today, various cards for identifying personal information, such as ID cards, credit cards, and cash cards, are in widespread use.
As described in "Microcomputer Handbook J P2S5 and P2S5" published by Ohmusha on May 25, it consists of a magnetic card with a magnetic stripe, and its storage capacity is limited to about 1700 bits.

Furthermore, the PIN code is simple, which poses a problem in terms of ensuring the security of personal information. Therefore, in order to increase storage capacity and enable complex password codes, cards made of resin with a standardized shape, rewritable non-volatile memory such as EEPROM, and communication with an external host computer are used. An IC (integrated circuit) card, which is equipped with a central processing unit that controls the memory, has been proposed, and its use as an alternative to passbooks and health cards is being considered.

Conventionally, such IC cards have been standardized in relation to a card reader, etc., and usually a set of non-volatile memory, data processing device, etc. is mounted separately on a relatively thin resin card board, or a set of these is mounted separately. Single chip 1
It is equipped with one.

[Problem that the invention seeks to solve]

However, IC cards are susceptible to mechanical stress and electrical damage during use, and the microcomputers mounted on the cards are easily damaged, which can easily cause them to become unable to communicate with the host computer or to be stored in storage. The inventors have discovered that information is easily lost, significantly reducing the reliability of the IC card.

An object of the present invention is to provide an IC card whose reliability can be improved even in a poor usage environment.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Means for solving problems]

A brief overview of typical inventions disclosed in this application is as follows.

That is, a plurality of sets of rewritable nonvolatile memory and a control circuit that controls the nonvolatile memory based on communication with a host computer are mounted on a card board, and each of the control circuits has self-protection against its own failure. The execution result of the diagnostic program is given to the host computer, and if the system can be operated normally, the host computer selectively puts it into operation.

[For production]

According to the above-mentioned means, even if one set of control circuits and nonvolatile memory is damaged, the remaining control circuits and nonvolatile memory are operated based on communication with the host computer, thereby making it possible to operate even in a poor usage environment. This also improves its reliability.

〔Example〕

FIG. 1 is a circuit diagram showing one embodiment of an IC card according to the present invention.

Although the IC card shown in the figure is not particularly limited, two microcomputer units M CU 1 and 'Cj M CU 2 each configured with a single chip,
It is mounted so as to be embedded in a resin card board CRD having standardized dimensions. The above-mentioned respective microcomputer units MCU1 and MCU2 are formed on one semiconductor substrate according to a known semiconductor integrated circuit manufacturing description,
Although not particularly shown, a central processing unit that performs data communication with the host computer HCU via a serial input/output interface that inputs and outputs serial data with the external host computer HCU; These include a program memory in which programs necessary for the operation of the device are stored, and a nonvolatile memory such as an EEPROM in which necessary data is stored in a rewritable manner under the control of the central processing unit.

Each of the microcomputer units MCU1 and MCU2 has a self-diagnosis program in its program memory (not shown) to determine whether or not it is capable of normal operation. The process is first executed after the IC card of the embodiment is inserted into a terminal device such as a card reader and initialized and reset. Each central processing unit stores data indicating its diagnostic results in a predetermined register, thereby setting a failure flag when normal operation is not possible, and
Set a normal flag when normal operation is possible. Here, the failure flag is set when there is no abnormality in at least the functional blocks necessary for executing the self-diagnosis program in each microcomputer unit, but there is an abnormality in any of the other parts. Furthermore, if neither the normal flag nor the abnormal flag is set, it is assumed that there is an abnormality in the functional blocks necessary for executing the self-diagnosis program.

In accordance with the International Standard (IS) of the International Organization for Standardization (So), the IC card of this embodiment has eight external terminals Pl to 8 that can be connected to a terminal device (not shown) that receives and processes the card. It has P8. External terminals Pl to P5 are connected to the microcomputer unit MC, respectively.
Commonly connected to the UI and MCU2. The external terminal P1 is supplied with the power supply voltage Vcc of one side of the circuit, the external terminal P2 is supplied with the power supply voltage GND of the other side of the circuit, and the external terminal P3 is supplied with the power supply voltage GND of the other side of the circuit.
is supplied with the reset signal R3T, and the external terminal P4 is supplied with the reference clock signal CLK. The reference clock signal CLK is used to enable each of the microcomputer units MCU1 and MCU2 to communicate with the host computer HCU in synchronization. External terminal P5 is
Necessary communication data is input/output between the host computer HCU and the serial input/output interface (not shown) in each of the microcomputer units MCUI and MCU2. Furthermore, the external terminal P6
and Pl are microcomputer units M C and Pl, respectively.
It is individually coupled to U1 and MCU2, and the external terminal P6 receives a chip select signal C3I for selectively enabling the microcomputer unit MCUI.
is supplied from the host computer HCU, and a chip select signal C32 for selectively enabling the other microcomputer unit (MCU2) is supplied from the host computer HCU to the external terminal P7. Note that the external terminal P8 is used as a spare terminal in preparation for future functional expansion.

When the host computer HCU is enabled to communicate with an IC card inserted into a terminal device (not shown), the host computer HCU serially checks whether a failure flag or a normal flag is set in each of the microcomputer units MCU1 and MCU2. External terminal P5 for data input/output
Distinguish through. That is, host computer HC
U is microcomputer unit MCU1 and MC
After the execution time of the self-diagnosis program in U2 has elapsed, the registers in which the failure flag and the normal flag are to be set are sequentially selected, and the stored data is sequentially read and determined. As a result, when it is determined that the failure flag is not set in any of the microcomputer units and the normal flag is set in both, the host computer HCU controls the respective microcomputer units included in the respective microcomputer units MCU1 and MCU2. For example, the above chip select signals C3I and C3 can be used to back up one of the nonvolatile memories.
2 to the operating level alternately according to predetermined timing, each microcomputer unit M
Communication with the same content is performed alternately between the CUI and the MCU2. Further, when it is determined that a failure flag is set in one of the microcomputer units and a normal flag is set in the other microcomputer unit by discrimination between the normal flag and the failure flag, the host computer HCU: The chip select signal to be supplied to the microcomputer unit for which the failure flag is set is always set to a non-operating level. Thereby, only the other microcomputer unit is made operational. At this time, as mentioned above, since one of the nonvolatile memories included in each of the microcomputer units MCU1 and MCU2 backs up the other, the - microcomputer unit becomes inoperable. Even if the IC card itself is used, the other microcomputer unit continues to allow normal operation of the IC card. When the host computer HCU on the - side is unable to recognize both the failure flag and the normal flag in the - side microcomputer unit, the microcomputer unit is determined to be malfunctioning. Similarly, the chip select signal to be supplied to the microcomputer unit is always set to a non-operating level.

Here, in the host computer HCU, when a failure of the negative microcomputer unit is detected,
The host computer HCU prompts the user to replace the ICV card by displaying a message indicating that the ICV card should be replaced on the terminal device into which the IC card is inserted.

Therefore, even if the - side microcomputer unit is damaged, the information stored in the IC card will not be lost and it can be replaced with a new IC card, which in turn simplifies the process of issuing IC card updates. be done.

In this embodiment, if a pair of microcomputer units MCUI and MCU2 are damaged at the same time, no measures can be taken to support it, but there is a probability that two microcomputer units MCU1 and MCU2 will be damaged at the same time. If the microcomputer units MCU1 and MCU2 are arranged asymmetrically with respect to the vertical and horizontal center lines CLI and CL2 of the card board CRD as shown in FIG. The probability that the microcomputer units MCUI and MCU2 are damaged at the same time is further reduced, and therefore there is very little need to consider the situation in which the pair of microcomputer units MCUI and MCU2 are damaged at the same time as a problem.

According to the embodiment described above, the following effects can be obtained.

(1) A pair of microcomputer units MCU1 and MCU2 are mounted on the card board CRD, and these microcomputer units MCU1 and MCU2 can operate alternately so that one backs up the other. Even if one IC card is damaged and becomes inoperable, the other microcomputer unit allows the IC card to continue to operate normally.

(2) As a result of the above effects, even in poor usage environments, communication with the host computer HCU will not become impossible, and data stored in the IC card will not be easily lost. Accordingly, the reliability of the IC card can be significantly improved.

(3) When the host computer HCU detects a failure in the - microcomputer unit, the host computer HCU sends a request to the terminal device into which the IC card is inserted to remind the user to replace the IC card. If the microcomputer unit on the other side is damaged, the information stored in the IC card will not be lost and a new microcomputer unit will be installed.
The IC card can be exchanged, and the work of issuing an IC card update is also simplified.

Although the invention made by the present inventor has been specifically explained based on Examples above, the present invention is not limited to the above Examples, and it should be noted that various changes can be made without departing from the gist of the invention. Not even.

For example, in the above embodiment, the host computer HCU can recognize abnormalities in the microcomputer units MCtJ1 and MC1J2 based on the data obtained by the self-diagnosis program in the microcomputer units MCtJ1 and MC1J2, but the host computer HCU is not limited to this. It is also possible to test the microcomputer unit mounted on the IC card based on the diagnostic program to recognize abnormalities in the microcomputer unit. Further, in the above embodiment, the alternating operation of both microcomputer units during normal operation and the switching operation when one of the microcomputer units is broken is controlled by the chip select signals C3I and C32, but the present invention is not limited to this. Instead, the host computer HCU includes a selection bit of the microcomputer unit in the communication data supplied to the C card, and the microcomputer unit is programmed to process the data as valid only if the predetermined selection bit is included. If so, there is no need to control the operations of both microcomputer units by the chip select signal. However, in each of the above cases, the host computer H
It is necessary to be careful that the load on the CU increases. Further, in the above embodiment, by using both the normal flag and the abnormal flag, the host computer is configured to be able to determine a failure in which the microcomputer unit cannot set the rain flag, but the present invention is not limited to such a configuration. First, in addition to setting only the failure flag, the execution of a failure diagnosis program by the host computer may also be used.

Furthermore, the number of microcomputer units mounted on one card board is not limited to two, but can be an appropriate number depending on the space factor and the like.

In the above explanation, we have mainly explained the case where the invention made by the present inventor is applied to an IC card equipped with two microcomputer units composed of a single chip, which is the field of application that formed the background of the invention. It is not limited. For example, the present invention can be applied to an IC card or the like in which a plurality of sets of nonvolatile memory chips such as EEPROM and microcomputer chips are mounted, which are devices that are functionally separated from each other. The present invention is applicable to a card board provided with at least a rewritable nonvolatile memory and a control circuit that controls the nonvolatile memory based on a signal supplied from the outside.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

That is, a plurality of sets of rewritable nonvolatile memory and a control circuit that controls the nonvolatile memory based on communication with a host computer are mounted on a card board,
Each of the control circuits above provides the host computer HCU with the execution results of the self-diagnosis program for its own failure, and when the control circuit can operate normally, the host computer HCU
Since the configuration is such that it is selectively activated by 1., even if the control circuit and non-volatile memory of the - group are damaged. Since the remaining control circuits and nonvolatile memory are operated under the control of the host computer HCU, reliability can be improved even in a poor usage environment.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing one embodiment of an IC card according to the present invention, and FIG. 2 is a plan view showing an example of the arrangement of a microcomputer unit on a card board. M CU 1... Microcomputer unit, H
CU2...Microcomputer unit, HCU/
- Host computer, C8I and CS2...chip select signal.

Claims (4)

[Claims] 1. A rewritable nonvolatile memory and a control circuit that controls the nonvolatile memory based on communication with the outside,
An IC card characterized by having multiple sets mounted on a card board. 2. 2. The IC card according to claim 1, wherein said pair of nonvolatile memory and control circuit are comprised of a single-chip microcomputer. 3. Each of the above control circuits is capable of executing a self-diagnosis program for its failure, and by giving the self-diagnosis results to a host computer, those that can operate normally are selectively enabled by the host computer. An IC card according to claim 1 or 2, characterized in that: 4. A patent characterized in that each of the above control circuits undergoes a failure diagnosis operation based on a program of a host computer, and those that can operate normally are selectively enabled by the host computer based on the diagnosis result. An IC card according to any one of claims 1 to 3.