JPH04352018A - Data processor - Google Patents

Abstract

PURPOSE:To make it possible to normally continue processing even at the time of generating instantaneous disconnection, instantaneous stop, or the like in a power supply by providing the data processor with a circuit for forming a power failure warning signal, and at the time of power failure, executing the saving processing of information to a memory. CONSTITUTION:When 12V power supply DC 12V is dropped to <=10.1V, a power failure warning signal A is outputted at time earier than the output of a reset signal B only by 8 to 15ms and a microprocessor 5 receives the signal A, executes a saving processing program 6a by interruption processing and saves information in processing to a storage area whose power supply is backed up by a battery or the like. Then a reset signal B is outputted and the operation of the microprocessor 5 or the like is stopped. When the 12V power supply DC 12V is dropped, a 5V power supply Vcc is also dropped and the whole control circuit is stopped operating. When the DC 12V of the 12V power supply is restored, the microprocessor 5 executes a restoring processing program 6a to execute restoring processing and normal operation is continued.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data processing device, and more particularly to a control circuit configuration and control method for an IC card reader/writer.

0002

2. Description of the Related Art FIG. 2(a) is a circuit diagram of a reset signal generating circuit in a conventional IC card reader/writer control circuit. This circuit uses one general-purpose IC 10 for generating a reset signal. An output pull-up resistor R20 and a timing setting capacitor C20 are arranged around the general-purpose IC 10 for generating a reset signal, and the resistor R20 and capacitor C20 are connected to the general-purpose IC 10 for generating a reset signal, and the power supply Vcc and the ground GND are connected to each other. A recommended circuit when using a general-purpose IC as the reset signal generating circuit is one in which power is supplied between the reset signal generating circuit and the reset signal generating circuit. For example, the voltage of the power supply Vcc is 5V, the resistance value of the resistor R20 is 4.7KΩ, and the capacitance of the capacitor C20 is 0.1 μF. The general-purpose IC 3 for generating a reset signal outputs a reset signal C according to the voltage level of the power supply Vcc. FIG. 2(b) shows an example of the output of the reset signal C corresponding to a change in the voltage level of the power supply Vcc in this conventional circuit. When the voltage of the power supply Vcc falls below a predetermined level, the reset signal C becomes low level. The predetermined level is approximately 4.2V. In such a configuration, when the power supply voltage drops during a power outage, the reset signal C is simply output. This applies not only to normal power shutdown operations, but also to instantaneous power outages caused by electrostatic discharge to input/output terminals or noise on the power line. On the other hand, in conventional reset signal generation circuits, a delay circuit consisting of a resistor and a capacitor is connected to the voltage detection terminal (SENSE), which is one of the input terminals of the general-purpose IC 3 for generating the reset signal. It is also recommended to detect only voltage drops above this level, but although this measure can prevent malfunctions due to minute fluctuations in the power supply voltage, it does not provide a fundamental solution. Therefore, the reset signal C generated by the conventional reset signal generation circuit
In a control circuit that only uses , if an instantaneous power failure occurs while the microprocessor of the IC card reader is processing, the microprocessor cannot afford to save the information being processed and is reset by the reset signal C, so the necessary information is not saved. is at risk of being lost.

0003

As described above, an IC card reader/writer using this type of reset signal generating circuit may lose necessary information due to an instantaneous power failure or the like, and may not be able to operate normally. The purpose of the present invention is to solve the problems of the prior art as described above, and to provide a circuit configuration and a circuit structure that can continue processing normally even if a momentary interruption or power outage occurs in the power supply. The present invention provides a data processing device such as an IC card reader/writer having a control method.

0004

[Means for Solving the Problems] A data processing device of the present invention has a configuration including a microprocessor, a storage area whose power source is backed up by a battery, etc., and a reset signal generation circuit. , a detection circuit that generates a signal (power outage warning signal) indicating that the power supply voltage has fallen below a predetermined value is provided separately or integrally with a reset signal generating circuit, and the power outage warning signal is connected to the microprocessor. It is something. As a specific configuration of the detection circuit, the circuit configuration when integrated with a reset signal generation circuit is described. This circuit includes a general-purpose IC for generating a first reset signal connected to a power supply terminal and a ground terminal; A second terminal connected to the power supply terminal and the ground terminal
a general-purpose IC for generating a reset signal, and receiving a signal generated by voltage division from the power supply voltage at a first input terminal of the general-purpose IC for generating a first reset signal, and generating a first reset signal. A general-purpose IC for generating a first reset signal uses a signal in which the delay time of the termination portion is determined by a first capacitor connected between a second input terminal and a ground terminal of the general-purpose IC for a power failure as a power outage warning signal. output, one end of the first resistor is connected to a power outage notice signal output terminal of a general-purpose IC for generating a first reset signal, and the other end is connected to a power supply terminal;
One end of the second resistor is a general-purpose I for generating the first reset signal.
The other end is connected to the output end of the power outage warning signal of C, and the other end is one end of the second capacitor and the general-purpose I for generating the second reset signal.
The second end of the second capacitor is connected to the first input terminal of C, and the other end of the second capacitor is connected to the ground terminal.
input to the first input terminal of a general-purpose IC for generating a reset signal, and terminated by a third capacitor connected between the second input terminal of the general-purpose IC for generating a second reset signal and the ground terminal. This circuit outputs a signal that determines the delay time of a portion as a reset signal from a general-purpose IC for generating a second reset signal.

[0005]

[Operation] In the control system of the control circuit configured as described above, in the event of a power outage, the power outage warning signal is outputted a predetermined time earlier than the reset signal, and the microprocessor receives the power outage warning signal and outputs the reset signal. Before this occurs, the information being processed is evacuated to a storage area whose power source is backed up by a battery or the like. Thereafter, a reset signal is output and the operation of the control circuit is stopped. After this, there will be no problem even if the power supply voltage drops below the threshold value at which the control circuit cannot operate. When the power supply voltage is restored, the microprocessor performs recovery processing using information saved in the storage area. Therefore, it goes without saying that it operates well when the power is turned on or stopped normally, but in the case of IC card readers/writers, etc., instantaneous power outages may occur due to static electricity being released to the input/output terminals or noise on the power line. Even if this occurs, normal operation can continue without adversely affecting the IC card.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1(a) is a circuit diagram mainly showing a signal generation circuit that generates a power outage warning signal and a reset signal in an IC card reader/writer to which the data processing device of the present invention is applied, and FIG. 3 is a time chart showing the operation of the circuit at different times. This signal generation circuit 4 is supplied with a 12V power (DC12V) and a 5V power (Vcc) from a power supply circuit in the control circuit, and has a voltage dividing circuit consisting of resistors R1, R2, R3, and a capacitor C1, and a power outage warning. It consists of a general-purpose IC1 for generating a reset signal that outputs a signal A, a signal delay circuit consisting of a switch SW, a resistor R5, and a capacitor C3, and a general-purpose IC2 for generating a reset signal that outputs a reset signal B. 12
Minute fluctuations are removed from the V power supply DC12V by a resistor R1 and a capacitor C1, and the voltage is divided by a resistor R2 and a resistor 3 to generate a monitored signal. 12V power supply DC12V
When the voltage becomes lower than a predetermined voltage (approximately 10.1 V), the general-purpose IC 1 for generating a reset signal generates a power outage warning signal A in response to the monitored signal. Since the general-purpose IC1 for generating a reset signal with an open collector output is employed, the power failure warning signal A is pulled up to the 5V power supply Vcc by the resistor R4 and transmitted to the microprocessor 5 and the like. The power outage warning signal A is delayed by the signal delay circuit 3 by a time determined by the time constant of the resistor R5 and the capacitor C3. General-purpose I for generating a reset signal in response to delayed power outage warning signal A
C2 generates a reset signal B. The reset signal B is transmitted to the microprocessor 5, peripheral LSI, etc. Capacitors C2 and C4 are used for timing adjustment at the end of the signal, and have a capacitance of 0.33 μF. The delay time in the signal delay circuit 3 is set to about 8 to 15 mS, and at this time, the resistor R5 is 22 KΩ and the capacitance of the capacitor C3 is 0.33 μF. Here, the switch SW is added for triggering from the outside, and does not directly affect the present invention. As explained above,
The circuit in this example is inexpensive and simply constructed using two general-purpose ICs.

The operation of the IC card reader/writer control circuit using the power outage warning signal A and reset signal B generated by this circuit at the time of a momentary power failure will be explained.
When 12V becomes 10.1V or lower, a power outage warning signal A is output 8 to 15 mS earlier than the reset signal B, and the microprocessor 5 receives the power outage warning signal A and executes the standby processing program 6a in interrupt processing. Run,
Information being processed is saved to a storage area whose power source is backed up by a battery or the like. Evacuation requires approximately 3 mS. Thereafter, a reset signal B is output and the operation of the microprocessor etc. is stopped. When the 12V power supply DC12V further decreases, the 5V power supply Vcc also decreases, and the operation of the entire control circuit stops. When the 12V power supply DC12V is restored, the microprocessor 5 executes the recovery processing program 6a to perform recovery processing using the information saved in the battery-backed storage area, and normal operation continues. Recovery processing will also be performed when the power is turned on for the first time, but this can be handled by performing setup processing or the like.

[0008]

[Effects of the Invention] As explained above, in this invention, even if a momentary power outage occurs due to electrostatic discharge to input/output terminals or noise on the power line, it will not adversely affect the IC card. Since the normal operation continues without interruption, the reliability and operability of the IC card reader/writer are improved.

[Brief explanation of drawings]

FIG. 1 is an embodiment of an IC card reader/writer to which the data processing device of the present invention is applied, and shows a circuit diagram and time chart of a signal generation circuit mainly used to generate a power outage warning signal and a reset signal. be.

FIG. 2 is a circuit diagram and a time chart of a reset signal generation circuit in a conventional IC card reader/writer control circuit.

[Explanation of symbols]

1, 2, 10 General-purpose IC3 for generating reset signal
Signal delay circuit 4
Signal generation circuit 5 Microprocessor 6a Save processing program 6b Recovery processing program A
Power outage warning signal B, C
Reset signal DC12V 12V power supply Vcc 5V power supply GND Ground potential

Claims (1)

[Claims] Claim 1: A data processing device controlled by a control circuit including a microprocessor and a reset signal generation circuit, the data processing device comprising a detection circuit that detects that a power supply voltage has fallen below a predetermined value and outputs a detection signal. , when the power supply is stopped, the detection circuit outputs the detection signal a predetermined time earlier than the reset signal output by the reset signal generation circuit, and upon receiving the detection signal, the microprocessor turns on the backup power supply. In the storage area you have,
Before the reset signal is generated, the information being processed is saved, the predetermined time is set to be longer than the processing time for saving the information being processed, and when the power supply voltage is restored, the microprocessor A data processing apparatus characterized in that a recovery process is performed using the information saved in the storage area.