JP2637109B2 - Processing unit for portable media - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention transmits a predetermined card power supply, a card clock signal and a card reset signal to a portable medium such as an IC card, The present invention relates to a portable medium processing device that exchanges information with the portable medium.

(Prior Art) As a portable medium, for example, an IC card is a plastic card having the same size as a credit card, in which an IC card chip such as a memory or a microcomputer is embedded. Since an IC card has a large memory storage capacity and a control unit such as a microcomputer, it is suitable for storing various information, data, and the like that require a large storage capacity. In addition, since it has a size suitable for carrying, various uses as a shopping card and a health check card are conceivable, and some of them have been put to practical use.

The IC card has a plurality of terminals exposed on an outer surface thereof. When the IC card is inserted into a portable medium processing device, for example, a reading / writing device (hereinafter, referred to as a card reader / writer), a contact provided on a contact portion of the card reader / writer and the IC card Are electrically connected to each other, so that card power is supplied from a card reader / writer and data is exchanged.

As such a conventional card reader / writer, the third one
The one shown in the figure is known.

A conventional card reader / writer shown in FIG. 3 uses a card power supply 21 of a predetermined power supply voltage for an IC card (not shown).
, A card reset signal 22, a card clock signal 23, and a serial transmission signal 24. Each of these card power supply 21, card reset signal 22, card clock signal 23, and serial transmission signal 24 is controlled independently.

That is, a microcomputer (hereinafter abbreviated as CPU) 1
The card power supply 21 is controlled by turning on / off the transistor TR19 based on the control command output from the terminal P2 of No. 1.

The card reset signal 22 is controlled based on a control command output from the terminal P1 of the CPU 11. The transmission line of the card reset signal 22 is connected to the output side of the drive power supply circuit 13 via the diode D1. Also, the terminal P0 of CPU11
Is supplied to one input terminal of the AND circuit G19, and the other input terminal of the AND circuit G19 is supplied with a clock signal from the clock generation circuit 15,
Since the card clock signal 23 is transmitted based on the logical product output of the logical product circuit G19, the card clock signal 23 is controlled based on the control command output from the terminal P0 of the CPU 11.

When the card power 21, the card reset signal 22, and the card clock signal 23 each having a predetermined voltage are transmitted to an IC card (not shown), the card power 21 and the card clock 21 are transmitted based on a preset control sequence. After the signal 23 is transmitted, the card reset signal 22 is released after a lapse of a predetermined time, for example, 50 ms, in order to prevent a malfunction of a circuit in the card. For example, card power
The card reset signal 22 is released by raising the card reset signal 22 from the L level to the H level after the elapse of 50 msec from the transmission of the signal 21. In this manner, information is exchanged with a portable medium such as an IC card after the card reset signal 22 is released.

(Problems to be Solved by the Invention) However, in the conventional example shown in FIG. 3, the card power supply 21, the card reset signal 22, and the card clock signal 23
Are controlled independently, so the card power supply
There is a possibility that the card reset signal 22 is released even though 21 is not transmitted. Therefore, even if the card power supply 21 or the card clock signal 23 is not transmitted, if the card reset signal 22 is released, important data stored in the portable medium is erased. I had a problem.

Further, the above card power supply 21, card reset signal 22,
The potentials of the card clock signal 23 and the serial transmission signal 24 do not have a circuit configuration such as, for example, pulling up a card reset signal to a driving power source and pulling down a card clock signal 23 to the ground. In addition, since the + 5V power supply of the card power supply 21 is shared with the drive power supply of other circuits, the voltage becomes very unstable, which may cause a malfunction or the like. became.

The present invention has been made in view of the above problems,
Is the IC when the card power is low or not supplied
A second object of the present invention is to provide a portable medium processing device capable of preventing the IC card from being activated and preventing the IC card from malfunctioning. I do.

[Structure of the Invention] (Means for Solving the Problems) Means provided by the present invention to achieve the above object are:
In a portable medium processing device that supplies power to the portable medium and exchanges information with the portable medium,
Power supply means for supplying a predetermined card power to the portable medium via a first transmission path to the portable medium; and a power supply means for supplying the card to the portable medium via a second transmission path to the portable medium. Clock supply means for supplying a clock signal;
Reset signal sending means for sending a card reset signal to the portable medium via a third transmission path to the portable medium; and card power and a card clock signal by the power supply means and the clock supply means. Control means for controlling each of the above-mentioned means so as to cancel the transmission of the reset signal by the reset signal sending means after a predetermined time from the supply to the portable medium, and the power supply means supplies the portable medium to the portable medium. Prohibiting means for prohibiting release of the reset signal by the reset signal transmitting means when the voltage of the card power supply falls below a predetermined voltage; and the power supply means provided on the third transmission line Supply of a clock signal by the clock signal supply means when the voltage of the power supply supplied to the portable medium is equal to or higher than a predetermined voltage. Permission means for permitting, further comprising a second transmission path for supplying a card reset signal to the portable medium, wherein the second transmission path is connected to a first transmission path for supplying a power supply voltage to the portable medium, A third transmission path for supplying a clock signal to the portable medium is characterized in that it is pull-down connected to ground.

(Operation) The first means of the present invention monitors the power supply state, and when the power supply is at the card power supply voltage, inhibits the cancellation of the card reset signal when the card power supply voltage is equal to or lower than a predetermined value. Things.

Further, a second means of the present invention is to prevent the card power supply from being sent out when an abnormality of the card power supply is detected.

(Example) Hereinafter, an example of the first means of the present invention will be described in detail with reference to the drawings, and an example of the second means of the present invention will be described together.

FIG. 1 is a circuit diagram showing an embodiment of the first means and the second means of the present invention, and FIG. 2 is an internal configuration diagram of the constant voltage power supply circuit shown in FIG.

CPU11 is a one-chip microcomputer,
When a voltage of +5 volts is applied to the reset terminal RESET, various control commands are executed based on a preset control sequence.

The control sequence of the CPU 11 will be specifically described. For example, a card power supply 21, a card reset signal 22, and a card clock signal 23, which will be described later, are transmitted to a portable medium such as an IC card (not shown), The card reset signal 22 is released after a predetermined time, for example, 50 ms, when the power supply 21 is in a stable state. That is, by raising the card reset signal 22 from the L level to the H level 50 ms after the card power supply 21 of the predetermined voltage is transmitted, the card reset signal 22 is released to exchange information with the portable medium. I do it. The exchange of information with the portable medium is performed by a serial transmission signal 24. That is, the gate circuit is connected from the terminal TXD of the CPU11.
The information from the CPU 11, that is, the serial transmission signal 24 is transmitted to the portable medium via G14 and G15 and the resistor R22, and the information from the portable medium, that is, the serial transmission signal 24 is transmitted through the resistor R23 and the gate circuit G16. Through CPU1
1 is applied to the terminal RXD.

The driving power supply circuit 13 supplies driving power of a predetermined power supply voltage to each circuit unit. That is, when a power supply switch (not shown) of a portable medium processing device for a portable medium, for example, a card reader / writer is turned on, a driving power supply is output to each circuit unit. The output terminal of the drive power supply circuit 13 is provided to the reset terminal RESET of the CPU 11 via the resistor R2, and when the power switch is turned on, the control operation of the CPU 11 is started. The output terminal of the drive power supply circuit 13 is connected to a card reset signal 22 via a diode D1.
Is connected to the transmission line for transmitting the card reset signal when the power supply voltage of the drive power supply is lower than a predetermined voltage.
This constitutes a second prohibiting means for prohibiting the release of the 22.

The input terminal IN of the power supply circuit 14 is connected to a transmission line for transmitting the card power supply 21, and the output terminal OUT of the power supply circuit 14 is connected to a transmission line for transmitting the card reset signal 22. The power supply circuit 14 monitors the power supply voltage of the card power supply 21. When the card power supply voltage falls below a predetermined voltage value, a first prohibiting means for prohibiting the cancellation of the card reset signal 22 described above. Is composed.

The card power supply control circuit 16 is controlled based on a control command of the terminal P1 of the CPU 11, and generates a card power supply 21 having a predetermined power supply voltage.

The input terminal 1 of the constant voltage power supply circuit 12 is connected to the + 12V power supply, the collector of the transistor Tr1 and the capacitor C19, and the terminal 2
Is connected to the base of transistor TR1 and
1 is connected to the emitter of the transistor TR1. The power supply voltage of the card power supply 21 is adjusted to a predetermined voltage by controlling the transistor TR1 based on the output signal output from the output terminal 2 of the constant voltage power supply circuit 12.

The terminal 3 of the constant voltage power supply circuit 12 is a short-circuit protection terminal. When the short-circuit protection terminal 3 is pulled down to the L level, the output terminal 2 of the constant voltage power supply circuit 12 is set to a low level. Therefore, it is possible to prevent the card power supply 21 from being sent to a portable medium (not shown). More specifically, the short-circuit protection terminal 3 of the constant-voltage power supply circuit 12, which is the blocking means, is connected to the collector of the transistor TR2. The transistor TR2 and the resistor R form a short-circuit detection circuit. When the excessive current is detected as a voltage drop of the detection resistor R due to the short circuit of the transistor TR2, the transistor TR2
Is turned on, the short-circuit protection terminal 3 of the above-described constant voltage power supply circuit 12 is pulled down to the L level, and the transmission of the card power supply 21 is prevented.

The short-circuit protection terminal 3 of the constant voltage power supply circuit 12 is connected to the terminal P1 of the CPU 11 via the resistor R15 and the gate circuit G3. The CPU 11 has a built-in control means for outputting a control signal via the terminal P1, and a control signal from the terminal P1 of the CPU 11, that is, a control signal for controlling on / off of the card power supply 21 is a short-circuit protection terminal. 3 given.

The terminal 4 of the constant voltage power supply circuit 12 is connected to the variable resistor VR and the resistor.
It is connected to the connection point with R14 and feeds back the state signal of the output state of the card power supply 21. That is, by adjusting the variable resistor VR, the state signal that returns to the terminal 4 of the constant voltage power supply circuit 12 changes, and the power supply voltage of the card power supply 21 can be adjusted.

The card power supply 21 generated in this manner is not shown.
It is sent to a portable medium such as an IC card. A transmission line for transmitting a card reset signal 22 via a resistor R3 and a resistor R21 is connected (pull-up connection) to a transmission line for transmitting the card power supply 21. The transmission line for transmitting 22 is connected to the output side of the power supply circuit 14 and the output side of the drive power supply circuit 13 as described above, and is connected to the CPU 11 via the gate circuit G2 formed using an open collector or the like. Connected to terminal P2. Therefore, the reset signal release command output from the terminal P2 of the CPU 11 is transmitted through the gate circuit G2.

The clock generation circuit 15 includes inverters G12 and G13, and resistors R17 and R17.
8, formed by capacitors C15 and C16 and crystal oscillator X, and generates a clock signal of a predetermined cycle. The clock signal generated by the clock generation circuit 15 is sent out as a card clock signal 23 via the gate circuit G1. The gate circuit G1 has a control terminal to which the power supply voltage of the card power supply 21 is applied, and has a permission means for permitting the transmission of the card clock signal 23 when the power supply voltage of the card power supply 21 is equal to or higher than a predetermined voltage set in advance. Make up. Also, the clock signal
The 23 supply lines are connected to a ground (pull-down connection) via a resistor RG as shown in FIG.

Next, the internal configuration of the constant voltage power supply circuit 12 will be described with reference to FIG.

When a predetermined input voltage is input to the input terminal 1, the start circuit 31 starts a start operation. Reference voltage generator 32
Generates a preset reference voltage according to a start signal from the start circuit 31, and supplies this reference voltage to the error amplifier 33.
To the non-inverting input terminal. A feedback signal, that is, a state signal indicating the output state of the card power supply 21 is fed back to the inverting input terminal of the error amplifier 33 via the terminal 4.
Therefore, the error amplifier 33 compares the feedback signal input via the terminal 4 with a predetermined reference voltage provided from the reference voltage generating circuit 32, amplifies the difference between the two, and outputs the amplified voltage. The overheat protection circuit 34 protects a circuit section from being damaged by overheating caused by an overcurrent. Darlington-coupled transistors 36 and 37 are connected to the overcurrent limiting circuit 35, and the card power supply 2 is controlled by controlling the base voltage of the transistor TR1 based on the output of the error amplifier 33.
Adjust the power supply voltage of 1 to a constant voltage.

Next, the operation of the first means of the present invention will be described with reference to FIGS. 1 and 2, and the operation of the second means of the present invention will be described together.

 First, the operation when the power is turned on will be described.

When a power switch (not shown) is turned on, a predetermined power supply voltage is sent from the drive power supply circuit 13 to each circuit unit. Further, a predetermined power supply voltage is supplied from the drive power supply circuit 13 to the reset terminal RESET of the CPU 11, and the CPU 11 starts a control operation based on a predetermined control sequence set in advance. Based on this preset control sequence, the terminals P1, P2 and TXD
When a control command is output from each of the above, the card power supply control circuit 16 is activated and outputs the card power supply 21 having a predetermined power supply voltage. The card power supply 21 having the predetermined voltage is sent to a portable medium (not shown).

On the other hand, in response to the supply of the power supply voltage from the drive power supply circuit 13, the clock generation circuit 15 starts oscillating and outputs a clock signal of a predetermined cycle. The control terminal of the gate circuit G1, which is a permission means for permitting the transmission of the card clock signal 23, is supplied with the above-described card power of the predetermined voltage, and the clock signal of the predetermined cycle from the clock generation circuit 15 is transmitted to the card. It is transmitted to a portable medium as a clock signal 23.

As described above, when the power switch (not shown) is turned on and the card power supply 21 and the card clock signal 23 are transmitted to the portable medium, a predetermined time, for example, 50 ms, elapses, and the card reset signal is released from the terminal P2 of the CPU 11. A command is sent. The command to release the card reset signal is transmitted through the gate circuit G2, and the card reset signal 22 is raised from the L level to the H level to release the card reset signal. In a portable medium, when a release signal that rises from the L level to the H level of the card reset signal is input, information can be exchanged with the card reader / writer.

Next, a case where the power supply voltage of the card power supply 21 decreases will be described.

Assuming that the power supply voltage of the card power supply 21 decreases due to a short circuit in the transmission line for transmitting the card power supply 21, the power supply circuit 14 monitors the power supply voltage of the gate power supply 21. When detecting that the voltage is equal to or lower than a predetermined voltage, the output side of the power supply circuit 14, that is, the transmission line of the card reset signal 22 is set to L level. When the transmission line for transmitting the card reset signal 22 is set to L level in this manner, the release of the card reset signal 22 is prohibited. That is, an L-level signal is transmitted as the card reset signal 22. Thus, in the portable medium, when the card reset signal 22 is set to the L level, the writing / reading operation of the data information is stopped, and the data content stored in advance is protected.

Next, a case where the power supply voltage of the drive power supply output from the drive power supply circuit 13 is reduced will be described.

For example, if one of the circuit sections in the card reader / writer causes a short circuit or the like and the output from the drive power supply circuit 13 decreases, the output side of the drive power supply circuit 13 transmits the card reset signal 22 via the diode D1. The transmission line for transmitting the card reset signal 22 is set to L level. Therefore, when the driving power supply voltage output from the driving power supply circuit 13 falls below a predetermined voltage, the cancellation of the card reset signal is prohibited. That is, the L-level card reset signal 22 is transmitted to the portable medium. Thus, in the portable medium, when the L-level card reset signal 22 is input, the read / write operation of the data information is stopped, and the data contents stored in advance can be reliably protected.

Further, when the card power supply 21 is short-circuited, the short-circuit protection terminal 3 is pulled down to the L level, and the constant-voltage power supply circuit 12 as blocking means for preventing transmission of the card power supply 21 is incorporated. The ON / OFF of the card power supply 21 can be controlled only by supplying a control signal to the terminal 3 for use. As a result, the card power control circuit can be simplified, and the cost can be further reduced.

[Effects of the Invention] According to the present invention, when the voltage of the card power supply supplied to the portable medium falls below a predetermined voltage, the reset signal transmission means is inhibited from canceling the reset signal transmission. I do.

When the voltage of the power supply supplied to the portable medium is equal to or higher than a predetermined voltage, the supply of the clock signal by the supply of the clock signal is permitted.

A transmission line for supplying a card reset signal is connected to a transmission line for supplying a power supply voltage to a portable medium by a pull-up connection, and a transmission line for supplying a clock signal to the portable medium is connected to a ground by a pull-down connection.

With this configuration, the portable medium is started only when the supply voltage to the portable medium is normal, and the reset signal and the clock signal are pulled up and down, respectively, so that the potential of the supply signal to the portable medium is increased. It is possible to prevent the portable medium from malfunctioning, which is maintained at a predetermined value.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention, FIG. 2 is an internal configuration diagram of the constant voltage power supply circuit shown in FIG. 1, and FIG. 3 is a circuit diagram showing a conventional example. 11 Microcomputer 12 Constant voltage power supply circuit 13 Drive power supply circuit 14 Power supply circuit 15 Clock generation circuit 16 Card power supply control circuit 21 Card power supply 22 Card reset signal 23 …… Card clock signal

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-105293 (JP, A) JP-A-62-44348 (JP, U)

Claims (1)

(57) [Claims] 1. A portable medium processing device for supplying power to a portable medium and exchanging information with the portable medium, wherein the portable medium is connected to the portable medium via a first transmission path to the portable medium. A power supply for supplying a predetermined card power; a clock supply for supplying a card clock signal to the portable medium via a second transmission path to the portable medium; and a third supply to the portable medium. A reset signal sending unit for sending a card reset signal to the portable medium via a transmission path; and a card power supply and a clock signal for the card supplied to the portable medium by the power supply unit and the clock supply unit. Control means for controlling each of the above means so as to release the reset signal sent by the reset signal sending means after a predetermined time; and portable by the power supply means Prohibiting means for prohibiting release of the reset signal by the reset signal transmitting means when the voltage of the card power supply supplied to the body drops below a predetermined voltage; and Permission means for permitting the supply of a clock signal by the clock signal supply means when the voltage of the power supplied to the portable medium by the power supply means is equal to or higher than a predetermined voltage. A second transmission path for supplying a card reset signal to the medium is connected to the first transmission path for supplying a power supply voltage to the portable medium by pull-up connection, and a third transmission path for supplying a clock signal to the portable medium. Is a portable medium processing device characterized by being connected to a ground by a pull-down connection.